diff --git a/.github/workflows/codecov.yml b/.github/workflows/codecov.yml
index c0fbc53..e60152a 100644
--- a/.github/workflows/codecov.yml
+++ b/.github/workflows/codecov.yml
@@ -15,10 +15,10 @@ jobs:
           - ubuntu-latest
 
         php:
-          - "8.2"
           - "8.3"
           - "8.4"
           - "8.5"
+          - "8.6"
 
     steps:
       - name: Checkout
diff --git a/.github/workflows/static-analysis.yml b/.github/workflows/static-analysis.yml
index 9976515..1bf077c 100644
--- a/.github/workflows/static-analysis.yml
+++ b/.github/workflows/static-analysis.yml
@@ -15,10 +15,10 @@ jobs:
           - ubuntu-latest
 
         php:
-          - "8.2"
           - "8.3"
           - "8.4"
           - "8.5"
+          - "8.6"
 
     steps:
       - name: Checkout
diff --git a/.laminas-ci.json b/.laminas-ci.json
index 29216fa..e827682 100644
--- a/.laminas-ci.json
+++ b/.laminas-ci.json
@@ -1,3 +1,6 @@
 {
+  "ignore_php_platform_requirements": {
+    "8.6": true
+  },
   "backwardCompatibilityCheck": true
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 382f245..c0fd414 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,418 +1,1204 @@
+# Changelog
+
+## 6.0.0 - Unreleased
+
+### Changed
+
+- **BC:** mail services are configured under `dot_mail.services`; `dot_mail.log` stays separate. A configuration in the old layout (`dot_mail.default`) now fails with an `InvalidArgumentException`. Move the service blocks as shown in `config/mail.global.php.dist`.
+- **BC:** `send()` restores the configured defaults after every attempt, successful or not: recipients, subject, body and attachments must be set again for every message. `getMessage()` returns a new object after each send.
+- **BC:** a missing or unreadable attachment now throws a `MailException` instead of being skipped.
+- **BC:** the attachment directory (`attachments.dir`) is scanned at send time instead of once at start-up, and files starting with a dot are skipped. Attachments are read with `DataPart::fromPath()`, so no file handles are left open.
+- **BC:** `send()` handles any `Throwable`, and the `MailException` it throws carries the original exception and code. `ResultInterface`, `MailResult` and `createMailResultFromException()` use `Throwable` instead of `Exception`.
+- **BC:** an exception thrown by a post-send listener propagates unchanged and is no longer reported as a send error, because the message was already delivered.
+- **BC:** the `esmtp` transport is built directly from `smtp_options` instead of through a DSN string. Credentials with special characters work, empty credentials are not sent, and `smtp_options.name` and `connection_time_limit` now take effect. `SmtpOptions::getName()` returns `?string` and defaults to `null`.
+- **BC:** a transport object or container service provided in `transport` is used as given and no longer replaced.
+- **BC:** `sendmail` is the default transport when the `transport` key is omitted, matching `config/mail.global.php.dist` and the documentation.
+- **BC:** `MailEvent::getResult()` returns `?ResultInterface`; the result is `null` in the pre-send event.
+- **BC:** a message that never received a body fails validation instead of being sent empty; an empty `body.content` in the configuration is no longer applied.
+- **BC:** the charset passed to `setBody()` and `body.charset` are used; `send()` only sets `utf-8` when no encoding is set.
+- **BC:** the minimum supported PHP version is 8.3 (`~8.3.0 || ~8.4.0 || ~8.5.0 || ~8.6.0`).
+- A failing log write no longer turns a delivered email into an error; `LogService::sent()` returns `false` when the log directory cannot be created, and writes use `LOCK_EX`.
+- Option getters fall back to defaults, so a minimal configuration no longer fails with uninitialized properties.
+
+### Added
+
+- `MailServiceInterface::reset()`, which restores the configured message and attachments. The `MailService` constructor accepts the default attachments as an optional fifth argument.
+- `MailServiceInterface` is aliased to `dot-mail.service.default`, so it can be injected by interface.
+- PHP 8.6 in the version constraint and in the CI matrix.
+- `laminas/laminas-stdlib` as a direct dependency.
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Support for PHP 8.2.
+- Unused attachment handling code from `Dot\Mail\Email`.
+
+### Fixed
+
+- `Email::addTo()` and the other address methods accept arrays of `Address` objects.
+- Transport aliases are matched case-insensitively (`ESMTP`, `SendMail`).
+- Missing `username`, `password` or `tls` keys in `smtp_options.connection_config` no longer raise warnings, and a username with special characters is encoded correctly.
+- `canCreate()` no longer reads an undefined array key for names with too few parts.
+- Detaching a listener that was never attached no longer removes a wrong entry.
+- Error messages for an invalid transport, an invalid event listener and an invalid port are accurate.
+
+## 5.4.3 - 2026-05-11
+
+### Changed
+
+- Nothing
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Attachments of a failed send no longer leak into the next email; the message body is reset after every send attempt ([#115](https://github.com/dotkernel/dot-mail/pull/115))
+
+## 5.4.2 - 2026-03-03
+
+### Changed
+
+- Nothing
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- `MailService`: fixed the email structure when sending multiple attachments ([#113](https://github.com/dotkernel/dot-mail/pull/113))
+
+## 5.4.1 - 2025-11-12
+
+### Changed
+
+- Updated OSS lifecycle metadata ([#111](https://github.com/dotkernel/dot-mail/pull/111))
+- Updated readme and documentation ([#112](https://github.com/dotkernel/dot-mail/pull/112))
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Nothing
+
+## 5.4.0 - 2025-11-03
+
+### Changed
+
+- Nothing
+
+### Added
+
+- Support for PHP 8.4 and 8.5 ([#104](https://github.com/dotkernel/dot-mail/pull/104))
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Support for PHP 8.1 ([#104](https://github.com/dotkernel/dot-mail/pull/104))
+
+### Fixed
+
+- Linking between documentation versions ([#105](https://github.com/dotkernel/dot-mail/pull/105))
+
+## 5.1.6 - 2025-11-03
+
+### Changed
+
+- Nothing
+
+### Added
+
+- Support for PHP 8.4 and 8.5 ([#103](https://github.com/dotkernel/dot-mail/pull/103))
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Support for PHP 8.1 ([#103](https://github.com/dotkernel/dot-mail/pull/103))
+
+### Fixed
+
+- Nothing
+
+## 5.0.4 - 2025-11-03
+
+### Changed
+
+- Documentation: version `5.0` is the default ([#75](https://github.com/dotkernel/dot-mail/pull/75))
+- Updated the v5 documentation ([#78](https://github.com/dotkernel/dot-mail/pull/78))
+- Bumped Psalm to 6.x ([#84](https://github.com/dotkernel/dot-mail/pull/84))
+
+### Added
+
+- Support for `laminas/laminas-servicemanager` 4.x ([#82](https://github.com/dotkernel/dot-mail/pull/82))
+- Upgrade guide from v4 to v5 ([#81](https://github.com/dotkernel/dot-mail/pull/81))
+- Support for PHP 8.4 and 8.5 ([#102](https://github.com/dotkernel/dot-mail/pull/102))
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Unused code inherited from version 4.0 ([#73](https://github.com/dotkernel/dot-mail/pull/73))
+- Support for PHP 8.1 ([#102](https://github.com/dotkernel/dot-mail/pull/102))
+
+### Fixed
+
+- Version links in the documentation footer ([#80](https://github.com/dotkernel/dot-mail/pull/80))
+- Attachments not working ([#87](https://github.com/dotkernel/dot-mail/pull/87))
+
+## 5.3.0 - 2025-03-04
+
+### Changed
+
+- Replaced Psalm with PHPStan ([#90](https://github.com/dotkernel/dot-mail/pull/90))
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Unused code ([#97](https://github.com/dotkernel/dot-mail/pull/97))
+
+### Fixed
+
+- Error caused by special characters ([#94](https://github.com/dotkernel/dot-mail/pull/94))
+
+## 5.1.5 - 2025-02-28
+
+### Changed
+
+- Nothing
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Error caused by special characters in the password ([#95](https://github.com/dotkernel/dot-mail/pull/95))
+
+## 5.1.4 - 2025-02-17
+
+### Changed
+
+- Nothing
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Attachments not working ([#88](https://github.com/dotkernel/dot-mail/pull/88))
+
+## 5.2.2 - 2025-02-14
+
+### Changed
+
+- Nothing
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Attachments not working ([#87](https://github.com/dotkernel/dot-mail/pull/87))
+
+## 5.2.1 - 2025-01-28
+
+### Changed
+
+- Bumped Psalm to 6.x ([#84](https://github.com/dotkernel/dot-mail/pull/84))
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Nothing
+
+## 5.2.0 - 2025-01-13
+
+### Changed
+
+- Nothing
+
+### Added
+
+- Support for `laminas/laminas-servicemanager` 4.x ([#82](https://github.com/dotkernel/dot-mail/pull/82))
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Nothing
+
+## 5.1.3 - 2025-01-06
+
+### Changed
+
+- Nothing
+
+### Added
+
+- Upgrade guide from v4 to v5 ([#81](https://github.com/dotkernel/dot-mail/pull/81))
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Nothing
+
+## 5.1.2 - 2024-12-19
+
+### Changed
+
+- Nothing
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Version links in the documentation footer ([#80](https://github.com/dotkernel/dot-mail/pull/80))
+
+## 5.1.1 - 2024-12-19
+
+### Changed
+
+- Documentation: version `5.0` is the default ([#75](https://github.com/dotkernel/dot-mail/pull/75))
+- Updated the v5 documentation ([#78](https://github.com/dotkernel/dot-mail/pull/78))
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Nothing
+
+## 5.1.0 - 2024-12-06
+
+### Changed
+
+- Nothing
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Unused code inherited from version 4.0 ([#73](https://github.com/dotkernel/dot-mail/pull/73))
+
+### Fixed
+
+- Nothing
+
+## 5.0.3 - 2024-12-03
+
+### Changed
+
+- Added `declare(strict_types=1)` to the configuration file ([#69](https://github.com/dotkernel/dot-mail/pull/69))
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Nothing
+
+## 5.0.2 - 2024-11-19
+
+### Changed
+
+- Cleaned the configuration file ([#67](https://github.com/dotkernel/dot-mail/pull/67))
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- The "from" name is displayed correctly ([#67](https://github.com/dotkernel/dot-mail/pull/67))
+
+## 5.0.1 - 2024-11-18
+
+### Changed
+
+- Nothing
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- SMTP transport: missing `port` array key ([#66](https://github.com/dotkernel/dot-mail/pull/66))
+
+## 5.0.0 - 2024-11-15
+
+### Changed
+
+- Replaced `laminas-mail` with `symfony/mailer` ([#65](https://github.com/dotkernel/dot-mail/pull/65))
+- Updated readme ([#61](https://github.com/dotkernel/dot-mail/pull/61))
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- `mime` and `imap` related functionality (see the upgrade guide from v4 to v5)
+
+### Fixed
+
+- Nothing
+
+## 4.3.0 - 2024-10-28
+
+### Changed
+
+- Final release of the wrapper over `laminas-mail`
+- Updated readme ([#61](https://github.com/dotkernel/dot-mail/pull/61))
+- Locked PHP at version 8.3 ([#64](https://github.com/dotkernel/dot-mail/pull/64))
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Nothing
+
+## 4.2.2 - 2024-06-28
+
+### Changed
+
+- Updated the documentation overview ([#59](https://github.com/dotkernel/dot-mail/pull/59))
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Nothing
+
+## 4.2.1 - 2024-06-18
+
+### Changed
+
+- Updated the documentation overview ([#58](https://github.com/dotkernel/dot-mail/pull/58))
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Nothing
+
+## 4.2.0 - 2024-05-03
+
+### Changed
+
+- Updated workflows ([#55](https://github.com/dotkernel/dot-mail/pull/55))
+
+### Added
+
+- v4 documentation ([#55](https://github.com/dotkernel/dot-mail/pull/55))
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Nothing
+
+## 4.1.1 - 2023-11-29
+
+### Changed
+
+- Bumped PHP to 8.3 ([#53](https://github.com/dotkernel/dot-mail/pull/53))
+
+### Added
+
+- Codecov badge ([#51](https://github.com/dotkernel/dot-mail/pull/51))
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Nothing
+
+## 4.1.0 - 2023-08-08
+
+### Changed
+
+- Psalm and phpcs fixes ([#47](https://github.com/dotkernel/dot-mail/pull/47))
+
+### Added
+
+- PHPUnit and tests ([#47](https://github.com/dotkernel/dot-mail/pull/47))
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Nothing
+
+## 4.0.4 - 2022-09-28
+
+### Changed
+
+- Updated error reporting
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Nothing
+
+## 3.4.6 - 2022-09-28
+
+### Changed
+
+- Updated error reporting
+
+### Added
+
+- Nothing
+
+### Deprecated
+
+- Nothing
+
+### Removed
+
+- Nothing
+
+### Fixed
+
+- Nothing
+
 ## 4.0.3 - 2022-08-31
 
 ### Changed
-* Improved email storage handling
-* Updated readme
+
+- Improved email storage handling
+- Updated readme
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
+
+- Nothing
 
 ## 4.0.2 - 2022-08-23
 
 ### Changed
-* Updated mail.global.php.dist
+
+- Updated mail.global.php.dist
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
+
+- Nothing
 
 ## 4.0.1 - 2022-08-12
 
 ### Changed
-* Updated readme
-* Updated mail.global.php.dist
+
+- Updated readme
+- Updated mail.global.php.dist
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
+
+- Nothing
 
 ## 4.0.0 - 2022-08-11
 
 ### Changed
-* Updated dependecies versions, including PHP to ~8.0.0 || ~8.1.0
-* Restricted laminas-mail version to >=2.17
+
+- Updated dependecies versions, including PHP to ~8.0.0 || ~8.1.0
+- Restricted laminas-mail version to >=2.17
 
 ### Added
-* Saving outgoing emails into folders
+
+- Saving outgoing emails into folders
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
+
+- Nothing
 
 ## 3.4.5 - 2022-08-30
 
 ### Changed
-* Updated readme
+
+- Updated readme
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
+
+- Nothing
 
 ## 3.4.4 - 2022-08-26
 
 ### Changed
-* Nothing
+
+- Nothing
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Updated check for storage
+
+- Updated check for storage
 
 ## 3.4.3 - 2022-08-25
 
 ### Changed
-* Improved email storage handling
+
+- Improved email storage handling
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
+
+- Nothing
 
 ## 3.4.2 - 2022-08-23
 
 ### Changed
-* Updated mail.global.php.dist
+
+- Updated mail.global.php.dist
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
+
+- Nothing
 
 ## 3.4.1 - 2022-08-12
 
 ### Changed
-* Nothing
+
+- Nothing
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* laminas/laminas-dependency-plugin
+
+- laminas/laminas-dependency-plugin
 
 ### Fixed
-* Nothing
+
+- Nothing
 
 ## 3.4.0 - 2022-08-10
 
 ### Changed
-* Nothing
+
+- Nothing
 
 ### Added
-* Saving outgoing emails into folders
+
+- Saving outgoing emails into folders
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
+
+- Nothing
 
 ## 3.3.1 - 2022-08-10
 
 ### Changed
-* Updated dependecies versions
-* Restricted laminas-mail version to <=2.16
+
+- Updated dependecies versions
+- Restricted laminas-mail version to <=2.16
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
+
+- Nothing
 
 ## 3.3.0 - 2022-06-20
 
 ### Changed
-* Updated PHP version to allow 8.0 and 8.1
+
+- Updated PHP version to allow 8.0 and 8.1
 
 ### Added
-* PHP 8.0 and 8.1 compatiblity
+
+- PHP 8.0 and 8.1 compatiblity
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
+
+- Nothing
 
 ## 2.1 - 2021-11-04
 
 ### Changed
-* Nothing
+
+- Nothing
 
 ### Added
-* Logging sent emails
+
+- Logging sent emails
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
+
+- Nothing
 
 ## 3.2.1 - 2021-09-24
 
 ### Changed
-* Nothing
+
+- Nothing
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* log/mail directory privileges
+
+- log/mail directory privileges
 
 ## 3.2.0 - 2021-09-23
 
 ### Changed
-* Nothing
+
+- Nothing
 
 ### Added
-* Logging sent emails
+
+- Logging sent emails
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
+
+- Nothing
 
 ## 3.1.1 - 2021-06-08
 
 ### Changed
-* Nothing
+
+- Nothing
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* fix issue #9: UTF-8 characters in message body 
+
+- fix issue #9: UTF-8 characters in message body
 
 ## 3.1.0 - 2020-11-03
 
 ### Changed
-* Composer 2 compatibility.
-* Update composer.json to require version 2 of laminas/laminas-dependency-plugin to be Composer 2 compatible.
+
+- Composer 2 compatibility.
+- Update composer.json to require version 2 of laminas/laminas-dependency-plugin to be Composer 2 compatible.
 
 ### Added
-* bump min version of laminas/laminas-mail
+
+- bump min version of laminas/laminas-mail
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* bump min version of laminas/laminas-dependency-plugin
-* bump min version of dotkernel/dot-event
+
+- bump min version of laminas/laminas-dependency-plugin
+- bump min version of dotkernel/dot-event
 
 ## 2.0.0 - 2020-01-30
 
 ### Changed
-* Laminas and Mezzio migration.
+
+- Laminas and Mezzio migration.
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Support
+
+- Support
 
 ### Fixed
-* Nothing
 
+- Nothing
 
 ## 1.0.0 - 2018-10-05
 
 ### Changed
-* Nothing
+
+- Nothing
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* TemplateRendererInterface requirement
-* Templating in mail support
+
+- TemplateRendererInterface requirement
+- Templating in mail support
 
 ### Fixed
-* Nothing
 
+- Nothing
 
 ## 0.2.0 - 2018-05-14
 
 ### Changed
-* updated `dot-twigrenderer` dependency
+
+- updated `dot-twigrenderer` dependency
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
 
+- Nothing
 
 ## 0.1.3 - 2017-04-21
 
 ### Changed
-* send mail does not rethrow exceptions anymore
+
+- send mail does not rethrow exceptions anymore
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
 
+- Nothing
 
 ## 0.1.2 - 2017-03-16
 
 ### Changed
-* updated composer.json
+
+- updated composer.json
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
 
+- Nothing
 
 ## 0.1.1 - 2017-03-11
 
 Updated php file headers doc blocks
 
 ### Added
-* Nothing
+
+- Nothing
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
 
+- Nothing
 
 ## 0.1.0 - 2017-03-09
 
 Initial tagged release
 
 ### Added
-* Everything
+
+- Everything
 
 ### Deprecated
-* Nothing
+
+- Nothing
 
 ### Removed
-* Nothing
+
+- Nothing
 
 ### Fixed
-* Nothing
+
+- Nothing
diff --git a/README.md b/README.md
index f3913d7..9c12fd3 100644
--- a/README.md
+++ b/README.md
@@ -10,26 +10,27 @@ Documentation is available at: https://docs.dotkernel.org/dot-mail/.
 
 ## Version History
 
-| Branch | Release    | PSR-11   | Mailer           | OSS Lifecycle                                                                                                                             | PHP Version                                                                                              |
-|--------|------------|----------|------------------|-------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------|
-| 5.2    | `>=5.2.0`  | 1 \|\| 2 | `symfony/mailer` | ![OSS Lifecycle](https://img.shields.io/osslifecycle?file_url=https%3A%2F%2Fgithub.com%2Fdotkernel%2Fdot-mail%2Fblob%2F5.2%2FOSSMETADATA) | ![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-mail/5.4.0) |
-| 5.1    | `<5.2.0`   | 1        | `symfony/mailer` | ![OSS Lifecycle](https://img.shields.io/osslifecycle?file_url=https%3A%2F%2Fgithub.com%2Fdotkernel%2Fdot-mail%2Fblob%2F5.1%2FOSSMETADATA) | ![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-mail/5.1.6) |
-| 5.0    | `<5.1.0`   | 1 \|\| 2 | `symfony/mailer` | ![OSS Lifecycle](https://img.shields.io/osslifecycle?file_url=https%3A%2F%2Fgithub.com%2Fdotkernel%2Fdot-mail%2Fblob%2F5.0%2FOSSMETADATA) | ![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-mail/5.0.4) |
-| 4.0    | `<=4.3.0`  | 1        | `laminas-mail`   | ![OSS Lifecycle](https://img.shields.io/osslifecycle?file_url=https%3A%2F%2Fgithub.com%2Fdotkernel%2Fdot-mail%2Fblob%2F4.0%2FOSSMETADATA) | ![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-mail/4.3.0) |
+| Branch | Release          | PSR-11   | Mailer           | OSS Lifecycle                                                                                                                             | PHP Version                                                                                              |
+|--------|------------------|----------|------------------|-------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------|
+| 6.0    | `>=6.0.0`        | 1 \|\| 2 | `symfony/mailer` | ![OSS Lifecycle](https://img.shields.io/osslifecycle?file_url=https%3A%2F%2Fgithub.com%2Fdotkernel%2Fdot-mail%2Fblob%2F6.0%2FOSSMETADATA) | ![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-mail/6.0.0) |
+| 5.2    | `>=5.2.0 <6.0.0` | 1 \|\| 2 | `symfony/mailer` | ![OSS Lifecycle](https://img.shields.io/osslifecycle?file_url=https%3A%2F%2Fgithub.com%2Fdotkernel%2Fdot-mail%2Fblob%2F5.2%2FOSSMETADATA) | ![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-mail/5.4.0) |
+| 5.1    | `<5.2.0`         | 1        | `symfony/mailer` | ![OSS Lifecycle](https://img.shields.io/osslifecycle?file_url=https%3A%2F%2Fgithub.com%2Fdotkernel%2Fdot-mail%2Fblob%2F5.1%2FOSSMETADATA) | ![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-mail/5.1.6) |
+| 5.0    | `<5.1.0`         | 1 \|\| 2 | `symfony/mailer` | ![OSS Lifecycle](https://img.shields.io/osslifecycle?file_url=https%3A%2F%2Fgithub.com%2Fdotkernel%2Fdot-mail%2Fblob%2F5.0%2FOSSMETADATA) | ![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-mail/5.0.4) |
+| 4.0    | `<=4.3.0`        | 1        | `laminas-mail`   | ![OSS Lifecycle](https://img.shields.io/osslifecycle?file_url=https%3A%2F%2Fgithub.com%2Fdotkernel%2Fdot-mail%2Fblob%2F4.0%2FOSSMETADATA) | ![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-mail/4.3.0) |
 
 ## Badges
 
 ![OSS Lifecycle](https://img.shields.io/osslifecycle/dotkernel/dot-mail)
-![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-mail/5.4.0)
+![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-mail/6.0.0)
 
 [![GitHub issues](https://img.shields.io/github/issues/dotkernel/dot-mail)](https://github.com/dotkernel/dot-mail/issues)
 [![GitHub forks](https://img.shields.io/github/forks/dotkernel/dot-mail)](https://github.com/dotkernel/dot-mail/network)
 [![GitHub stars](https://img.shields.io/github/stars/dotkernel/dot-mail)](https://github.com/dotkernel/dot-mail/stargazers)
-[![GitHub license](https://img.shields.io/github/license/dotkernel/dot-mail)](https://github.com/dotkernel/dot-mail/blob/5.2/LICENSE.md)
+[![GitHub license](https://img.shields.io/github/license/dotkernel/dot-mail)](https://github.com/dotkernel/dot-mail/blob/6.0/LICENSE.md)
 
-[![Build Static](https://github.com/dotkernel/dot-mail/actions/workflows/continuous-integration.yml/badge.svg?branch=5.2)](https://github.com/dotkernel/dot-mail/actions/workflows/continuous-integration.yml)
-[![codecov](https://codecov.io/gh/dotkernel/dot-mail/branch/5.2/graph/badge.svg?token=G51NEHYKD3)](https://codecov.io/gh/dotkernel/dot-mail)
-[![PHPStan](https://github.com/dotkernel/dot-mail/actions/workflows/static-analysis.yml/badge.svg?branch=5.2)](https://github.com/dotkernel/dot-mail/actions/workflows/static-analysis.yml)
+[![Build Static](https://github.com/dotkernel/dot-mail/actions/workflows/continuous-integration.yml/badge.svg?branch=6.0)](https://github.com/dotkernel/dot-mail/actions/workflows/continuous-integration.yml)
+[![codecov](https://codecov.io/gh/dotkernel/dot-mail/branch/6.0/graph/badge.svg?token=G51NEHYKD3)](https://codecov.io/gh/dotkernel/dot-mail)
+[![PHPStan](https://github.com/dotkernel/dot-mail/actions/workflows/static-analysis.yml/badge.svg?branch=6.0)](https://github.com/dotkernel/dot-mail/actions/workflows/static-analysis.yml)
 
 ## Installation
 
diff --git a/SECURITY.md b/SECURITY.md
index d7fa46f..088dc6a 100644
--- a/SECURITY.md
+++ b/SECURITY.md
@@ -4,6 +4,7 @@
 
 | Version | Supported                                                                                                                                 | PHP Version                                                                                              |
 |---------|-------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------|
+| 6.0     | ![OSS Lifecycle](https://img.shields.io/osslifecycle?file_url=https%3A%2F%2Fgithub.com%2Fdotkernel%2Fdot-mail%2Fblob%2F6.0%2FOSSMETADATA) | ![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-mail/6.0.0) |
 | 5.2     | ![OSS Lifecycle](https://img.shields.io/osslifecycle?file_url=https%3A%2F%2Fgithub.com%2Fdotkernel%2Fdot-mail%2Fblob%2F5.2%2FOSSMETADATA) | ![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-mail/5.2.0) |
 | 5.1     | ![OSS Lifecycle](https://img.shields.io/osslifecycle?file_url=https%3A%2F%2Fgithub.com%2Fdotkernel%2Fdot-mail%2Fblob%2F5.1%2FOSSMETADATA) | ![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-mail/5.1.0) |
 | 5.0     | ![OSS Lifecycle](https://img.shields.io/osslifecycle?file_url=https%3A%2F%2Fgithub.com%2Fdotkernel%2Fdot-mail%2Fblob%2F5.0%2FOSSMETADATA) | ![PHP from Packagist (specify version)](https://img.shields.io/packagist/php-v/dotkernel/dot-mail/5.0.0) |
diff --git a/config/mail.global.php.dist b/config/mail.global.php.dist
index ad0711d..cec53ff 100644
--- a/config/mail.global.php.dist
+++ b/config/mail.global.php.dist
@@ -9,78 +9,81 @@ return [
      * what you'll usually do, these configs provide just defaults and options that remain the same for all mails
      */
     'dot_mail' => [
-        //the key is the mail service name, this is the default one, which does not extend any configuration
-        'default' => [
-            //message configuration
-            'message_options' => [
-                //from email address of the email
-                'from' => '',
-                //from name to be displayed instead of from address
-                'from_name' => '',
-                //reply-to email address of the email
-                'reply_to' => '',
-                //replyTo name to be displayed instead of the address
-                'reply_to_name' => '',
-                //destination email address as string or a list of email addresses
-                'to' => [],
-                //copy destination addresses
-                'cc' => [],
-                //hidden copy destination addresses
-                'bcc' => [],
-                //email subject
-                'subject' => '',
-                //body options - content can be plain text, HTML
-                'body' => [
-                    'content' => '',
-                    'charset' => 'utf-8',
-                ],
-                //attachments config
-                'attachments' => [
-                    'files' => [],
-                    'dir'   => [
-                        'iterate'   => false,
-                        'path'      => 'data/mail/attachments',
-                        'recursive' => false,
+        // option to log the SENT emails
+        'log'      => [
+            'sent' => getcwd() . '/log/mail/sent.log',
+        ],
+        //the mail services, indexed by service name
+        'services' => [
+            //the key is the mail service name, this is the default one
+            'default' => [
+                //message configuration
+                'message_options' => [
+                    //from email address of the email
+                    'from' => '',
+                    //from name to be displayed instead of from address
+                    'from_name' => '',
+                    //reply-to email address of the email
+                    'reply_to' => '',
+                    //replyTo name to be displayed instead of the address
+                    'reply_to_name' => '',
+                    //destination email address as string or a list of email addresses
+                    'to' => [],
+                    //copy destination addresses
+                    'cc' => [],
+                    //hidden copy destination addresses
+                    'bcc' => [],
+                    //email subject
+                    'subject' => '',
+                    //body options - content can be plain text, HTML
+                    'body' => [
+                        'content' => '',
+                        'charset' => 'utf-8',
+                    ],
+                    //attachments config
+                    'attachments' => [
+                        'files' => [],
+                        'dir'   => [
+                            'iterate'   => false,
+                            'path'      => 'data/mail/attachments',
+                            'recursive' => false,
+                        ],
                     ],
                 ],
-            ],
-            /**
-             * the mail transport to use can be any class implementing
-             * Symfony\Component\Mailer\Transport\TransportInterface
-             *
-             * for standard mail transports, you can use these aliases:
-             * - sendmail  => Symfony\Component\Mailer\Transport\SendmailTransport
-             * - esmtp     => Symfony\Component\Mailer\Transport\Smtp\EsmtpTransport
-             *
-             * defaults to sendmail
-             **/
-            'transport' => 'sendmail',
-            //options that will be used only if esmtp adapter is used
-            'smtp_options' => [
-                //hostname or IP address of the mail server
-                'host' => '',
-                //port of the mail server - 587 or 465 for secure connections
-                'port'              => 587,
-                'connection_config' => [
-                    //the smtp authentication identity
-                    'username' => '',
-                    //the smtp authentication credential
-                    'password' => '',
-                    /**
-                     * tls will run by default on this component, use:
-                     *
-                     * null  - to avoid interfering with automatic encryption
-                     * false - to disable automatic encryption
-                     *
-                     * It's not recommended to disable TLS while connecting to an SMTP server over the Internet
-                     **/
-                    'tls' => null,
+                /**
+                 * the mail transport to use can be any class implementing
+                 * Symfony\Component\Mailer\Transport\TransportInterface
+                 *
+                 * for standard mail transports, you can use these aliases:
+                 * - sendmail  => Symfony\Component\Mailer\Transport\SendmailTransport
+                 * - esmtp     => Symfony\Component\Mailer\Transport\Smtp\EsmtpTransport
+                 *
+                 * defaults to sendmail
+                 **/
+                'transport' => 'sendmail',
+                //options that will be used only if esmtp adapter is used
+                'smtp_options' => [
+                    //hostname or IP address of the mail server
+                    'host' => '',
+                    //port of the mail server - 587 or 465 for secure connections
+                    'port'              => 587,
+                    'connection_config' => [
+                        //the smtp authentication identity
+                        'username' => '',
+                        //the smtp authentication credential
+                        'password' => '',
+                        /**
+                         * tls will run by default on this component, use:
+                         *
+                         * null  - to avoid interfering with automatic encryption
+                         * false - to disable automatic encryption
+                         *
+                         * It's not recommended to disable TLS while connecting to an SMTP server over the Internet
+                         **/
+                        'tls' => null,
+                    ],
                 ],
             ],
         ],
-        // option to log the SENT emails
-        'log' => [
-            'sent' => getcwd() . '/log/mail/sent.log',
-        ],
     ],
 ];
diff --git a/src/ConfigProvider.php b/src/ConfigProvider.php
index 6f6ae8e..53ec221 100644
--- a/src/ConfigProvider.php
+++ b/src/ConfigProvider.php
@@ -9,6 +9,7 @@
 use Dot\Mail\Factory\MailServiceAbstractFactory;
 use Dot\Mail\Service\LogService;
 use Dot\Mail\Service\LogServiceInterface;
+use Dot\Mail\Service\MailServiceInterface;
 
 class ConfigProvider
 {
@@ -26,7 +27,8 @@ public function getDependencyConfig(): array
                 LogService::class => LogServiceFactory::class,
             ],
             'aliases'            => [
-                LogServiceInterface::class => LogService::class,
+                LogServiceInterface::class  => LogService::class,
+                MailServiceInterface::class => 'dot-mail.service.default',
             ],
             'abstract_factories' => [
                 MailServiceAbstractFactory::class,
diff --git a/src/Email.php b/src/Email.php
index 7640ce7..0d605e6 100644
--- a/src/Email.php
+++ b/src/Email.php
@@ -12,20 +12,12 @@
 use Symfony\Component\Mime\Message;
 use Symfony\Component\Mime\Part\AbstractPart;
 use Symfony\Component\Mime\Part\Multipart\AlternativePart;
-use Symfony\Component\Mime\Part\Multipart\MixedPart;
-use Symfony\Component\Mime\Part\Multipart\RelatedPart;
 use Symfony\Component\Mime\Part\TextPart;
 
-use function array_filter;
-use function array_merge;
-use function array_unique;
-use function array_values;
 use function is_array;
 use function is_string;
-use function preg_match_all;
 use function sprintf;
 use function sscanf;
-use function str_replace;
 
 class Email extends Message
 {
@@ -48,7 +40,6 @@ class Email extends Message
     private ?string $html        = null;
 
     private ?string $htmlCharset = null;
-    private array $attachments   = [];
 
     public function subject(string $subject): static
     {
@@ -265,8 +256,8 @@ public function ensureValidity(): void
 
     private function ensureBodyValid(): void
     {
-        if (null === $this->text && null === $this->html && ! $this->attachments) {
-            throw new LogicException('A message must have a text or an HTML part or attachments.');
+        if (null === $this->text && null === $this->html) {
+            throw new LogicException('A message must have a text or an HTML part.');
         }
     }
 
@@ -274,81 +265,15 @@ private function generateBody(): AbstractPart
     {
         $this->ensureBodyValid();
 
-        [$htmlPart, $otherParts, $relatedParts] = $this->prepareParts();
-
         $part = null === $this->text ? null : new TextPart($this->text, $this->textCharset);
-        if (null !== $htmlPart) {
-            if (null !== $part) {
-                $part = new AlternativePart($part, $htmlPart);
-            } else {
-                $part = $htmlPart;
-            }
-        }
-
-        if ($relatedParts) {
-            $part = new RelatedPart($part, ...$relatedParts);
-        }
-
-        if ($otherParts) {
-            if ($part) {
-                $part = new MixedPart($part, ...$otherParts);
-            } else {
-                $part = new MixedPart(...$otherParts);
-            }
+        if (null !== $this->html) {
+            $htmlPart = new TextPart($this->html, $this->htmlCharset, 'html');
+            $part     = null !== $part ? new AlternativePart($part, $htmlPart) : $htmlPart;
         }
 
         return $part ?? new TextPart((string) $this->text, $this->textCharset);
     }
 
-    private function prepareParts(): array
-    {
-        $names    = [];
-        $htmlPart = null;
-        $html     = $this->html;
-        if (null !== $html) {
-            $htmlPart = new TextPart($html, $this->htmlCharset, 'html');
-            $html     = $htmlPart->getBody();
-
-            $regexes    = [
-                '<img\s+[^>]*src\s*=\s*(?:([\'"])cid:(.+?)\\1|cid:([^>\s]+))',
-                '<\w+\s+[^>]*background\s*=\s*(?:([\'"])cid:(.+?)\\1|cid:([^>\s]+))',
-            ];
-            $tmpMatches = [];
-            foreach ($regexes as $regex) {
-                preg_match_all('/' . $regex . '/i', $html, $tmpMatches);
-                $names = array_merge($names, $tmpMatches[2], $tmpMatches[3]);
-            }
-            $names = array_filter(array_unique($names));
-        }
-
-        $otherParts = $relatedParts = [];
-        foreach ($this->attachments as $part) {
-            foreach ($names as $name) {
-                if ($name !== $part->getName() && (! $part->hasContentId() || $name !== $part->getContentId())) {
-                    continue;
-                }
-                if (isset($relatedParts[$name])) {
-                    continue 2;
-                }
-
-                if ($name !== $part->getContentId()) {
-                    $html = str_replace('cid:' . $name, 'cid:' . $part->getContentId(), $html, $count);
-                }
-                $relatedParts[$name] = $part;
-                $part->setName($part->getContentId())->asInline();
-
-                continue 2;
-            }
-
-            $otherParts[] = $part;
-        }
-        if (null !== $htmlPart) {
-            $htmlPart = new TextPart($html, $this->htmlCharset, 'html');
-        }
-
-        return [$htmlPart, $otherParts, array_values($relatedParts)];
-    }
-
     private function setHeaderBody(string $type, string $name, mixed $body): static
     {
         $this->getHeaders()->setHeaderBody($type, $name, $body);
diff --git a/src/Event/MailEvent.php b/src/Event/MailEvent.php
index 5ad801f..a835825 100644
--- a/src/Event/MailEvent.php
+++ b/src/Event/MailEvent.php
@@ -21,7 +21,7 @@ class MailEvent extends Event
     public const EVENT_MAIL_SEND_ERROR = 'event.mail.send.error';
 
     protected MailServiceInterface $mailService;
-    protected ResultInterface $result;
+    protected ?ResultInterface $result = null;
 
     public function __construct(MailServiceInterface $mailService, string $name = self::EVENT_MAIL_PRE_SEND)
     {
@@ -39,7 +39,7 @@ public function setMailService(MailServiceInterface $mailService): void
         $this->mailService = $mailService;
     }
 
-    public function getResult(): ResultInterface
+    public function getResult(): ?ResultInterface
     {
         return $this->result;
     }
diff --git a/src/Factory/AbstractMailFactory.php b/src/Factory/AbstractMailFactory.php
index 6ada22a..1794f46 100644
--- a/src/Factory/AbstractMailFactory.php
+++ b/src/Factory/AbstractMailFactory.php
@@ -4,6 +4,7 @@
 
 namespace Dot\Mail\Factory;
 
+use Dot\Mail\Exception\InvalidArgumentException;
 use Laminas\ServiceManager\Factory\AbstractFactoryInterface;
 use Psr\Container\ContainerExceptionInterface;
 use Psr\Container\ContainerInterface;
@@ -13,11 +14,14 @@
 use function count;
 use function explode;
 use function is_array;
+use function sprintf;
 
 abstract class AbstractMailFactory implements AbstractFactoryInterface
 {
     public const DOT_MAIL_PART = 'dot-mail';
     public const SPECIFIC_PART = '';
+    public const SERVICES_KEY  = 'services';
+    public const LOG_KEY       = 'log';
 
     protected string $configKey = 'dot_mail';
     protected array $config     = [];
@@ -41,14 +45,34 @@ public function canCreate(ContainerInterface $container, $requestedName): bool
     }
 
     /**
+     * Returns the configured mail services, indexed by name (the `dot_mail.services` key).
+     *
      * @throws ContainerExceptionInterface
      * @throws NotFoundExceptionInterface
+     * @throws InvalidArgumentException When the configuration uses the pre-6.0 layout.
      */
     public function getConfig(ContainerInterface $container): array
     {
         $config = $container->get('config');
-        if (isset($config[$this->configKey]) && is_array($config[$this->configKey])) {
-            $this->config = $config[$this->configKey];
+        if (! isset($config[$this->configKey]) || ! is_array($config[$this->configKey])) {
+            return $this->config;
+        }
+
+        $mailConfig = $config[$this->configKey];
+        if (isset($mailConfig[self::SERVICES_KEY]) && is_array($mailConfig[self::SERVICES_KEY])) {
+            $this->config = $mailConfig[self::SERVICES_KEY];
+            return $this->config;
+        }
+
+        foreach ($mailConfig as $key => $value) {
+            if ($key !== self::LOG_KEY && is_array($value)) {
+                throw new InvalidArgumentException(sprintf(
+                    'Mail service "%s" must be configured under "%s.%s"; see the upgrade guide to version 6',
+                    $key,
+                    $this->configKey,
+                    self::SERVICES_KEY
+                ));
+            }
         }
 
         return $this->config;
diff --git a/src/Factory/MailServiceAbstractFactory.php b/src/Factory/MailServiceAbstractFactory.php
index d104550..136566d 100644
--- a/src/Factory/MailServiceAbstractFactory.php
+++ b/src/Factory/MailServiceAbstractFactory.php
@@ -4,7 +4,6 @@
 
 namespace Dot\Mail\Factory;
 
-use DirectoryIterator;
 use Dot\Mail\Email;
 use Dot\Mail\Event\MailEventListenerAwareInterface;
 use Dot\Mail\Event\MailEventListenerInterface;
@@ -14,24 +13,19 @@
 use Dot\Mail\Service\LogServiceInterface;
 use Dot\Mail\Service\MailService;
 use Dot\Mail\Service\MailServiceInterface;
-use FilesystemIterator;
 use Psr\Container\ContainerExceptionInterface;
 use Psr\Container\ContainerInterface;
 use Psr\Container\NotFoundExceptionInterface;
-use RecursiveDirectoryIterator;
-use RecursiveIteratorIterator;
-use Symfony\Component\Mailer\Transport;
 use Symfony\Component\Mailer\Transport\Smtp\EsmtpTransport;
+use Symfony\Component\Mailer\Transport\Smtp\Stream\SocketStream;
 use Symfony\Component\Mailer\Transport\TransportInterface;
 
 use function explode;
 use function gettype;
 use function is_array;
-use function is_dir;
 use function is_object;
 use function is_string;
 use function is_subclass_of;
-use function rawurlencode;
 use function sprintf;
 
 class MailServiceAbstractFactory extends AbstractMailFactory
@@ -61,45 +55,12 @@ public function __invoke(
             )
         );
 
-        $logService = $container->get(LogServiceInterface::class);
-        $message    = $this->createMessage();
-        $transport  = $this->createTransport($container);
+        $logService  = $container->get(LogServiceInterface::class);
+        $message     = $this->createMessage();
+        $transport   = $this->createTransport($container);
+        $attachments = $this->mailOptions->getMessageOptions()->getAttachments()->getFiles();
 
-        $mailService = new MailService($logService, $message, $transport, $this->mailOptions);
-
-        //set subject
-        $mailService->setSubject($this->mailOptions->getMessageOptions()->getSubject());
-
-        $body = $this->mailOptions->getMessageOptions()->getBody();
-
-        $mailService->setBody($body->getContent(), $body->getCharset());
-
-        //attach files
-        $files = $this->mailOptions->getMessageOptions()->getAttachments()->getFiles();
-        $mailService->addAttachments($files);
-
-        //attach files from dir
-        $dir = $this->mailOptions->getMessageOptions()->getAttachments()->getDir();
-
-        if ($dir['iterate'] === true && is_string($dir['path']) && is_dir($dir['path'])) {
-            $files = $dir['recursive'] === true
-                ? new RecursiveIteratorIterator(
-                    new RecursiveDirectoryIterator(
-                        $dir['path'],
-                        FilesystemIterator::SKIP_DOTS
-                    ),
-                    RecursiveIteratorIterator::CHILD_FIRST
-                )
-                : new DirectoryIterator($dir['path']);
-
-            foreach ($files as $fileInfo) {
-                if ($fileInfo->isDir()) {
-                    continue;
-                }
-
-                $mailService->addAttachment($fileInfo->getPathname());
-            }
-        }
+        $mailService = new MailService($logService, $message, $transport, $this->mailOptions, $attachments);
 
         $this->attachMailListeners($mailService, $container);
         return $mailService;
@@ -135,6 +96,13 @@ protected function createMessage(): Email
             $message->setBcc($bcc);
         }
 
+        $message->subject($options->getSubject());
+
+        $body = $options->getBody();
+        if ($body->getContent() !== '') {
+            $message->html($body->getContent(), $body->getCharset());
+        }
+
         return $message;
     }
 
@@ -145,25 +113,32 @@ protected function createMessage(): Email
     protected function createTransport(ContainerInterface $container): TransportInterface
     {
         $adapter = $this->mailOptions->getTransport();
+
+        //a transport object provided by the user is used as it is
         if ($adapter instanceof TransportInterface) {
-            return $this->setupTransportConfig($adapter);
+            return $adapter;
         }
 
         //check is adapter is a service
         if ($container->has($adapter)) {
             $transport = $container->get($adapter);
             if ($transport instanceof TransportInterface) {
-                return $this->setupTransportConfig($transport);
-            } else {
-                throw new InvalidArgumentException(
-                    'Provided transport service does not return a ' . TransportInterface::class . ' instance'
-                );
+                return $transport;
             }
+
+            throw new InvalidArgumentException(
+                'Provided transport service does not return a ' . TransportInterface::class . ' instance'
+            );
+        }
+
+        //the esmtp alias is configured from the smtp options
+        if ($adapter === EsmtpTransport::class) {
+            return $this->createEsmtpTransport();
         }
 
         //check is the adapter is Symfony default adapter
         if (is_subclass_of($adapter, TransportInterface::class)) {
-            return $this->setupTransportConfig(new $adapter());
+            return new $adapter();
         }
 
         //the adapter is not valid - throw exception
@@ -176,16 +151,35 @@ protected function createTransport(ContainerInterface $container): TransportInte
         );
     }
 
-    protected function setupTransportConfig(TransportInterface $transport): TransportInterface
+    protected function createEsmtpTransport(): EsmtpTransport
     {
-        if ($transport instanceof EsmtpTransport) {
-            $user      = $this->mailOptions->getSmtpOptions()->getConnectionConfig()['username'];
-            $pass      = rawurlencode($this->mailOptions->getSmtpOptions()->getConnectionConfig()['password']);
-            $tls       = $this->mailOptions->getSmtpOptions()->getConnectionConfig()['tls'] === false ? 'false' : null;
-            $port      = $this->mailOptions->getSmtpOptions()->getPort();
-            $host      = $this->mailOptions->getSmtpOptions()->getHost();
-            $transport = Transport::fromDsn('smtp://' . $user . ':' . $pass . '@' . $host . ':' . $port
-                . '?auto_tls=' . $tls);
+        $smtp       = $this->mailOptions->getSmtpOptions();
+        $connection = $smtp->getConnectionConfig();
+        $tls        = $connection['tls'] ?? null;
+
+        //null leaves the encryption to the transport (automatic), false disables it
+        $transport = new EsmtpTransport($smtp->getHost(), $smtp->getPort(), $tls === false ? false : null);
+        $transport->setAutoTls($tls !== false);
+
+        $username = (string) ($connection['username'] ?? '');
+        if ($username !== '') {
+            $transport->setUsername($username);
+        }
+
+        $password = (string) ($connection['password'] ?? '');
+        if ($password !== '') {
+            $transport->setPassword($password);
+        }
+
+        $name = $smtp->getName();
+        if ($name !== null) {
+            $transport->setLocalDomain($name);
+        }
+
+        $timeLimit = $smtp->getConnectionTimeLimit();
+        $stream    = $transport->getStream();
+        if ($timeLimit !== null && $stream instanceof SocketStream) {
+            $stream->setTimeout((float) $timeLimit);
         }
 
         return $transport;
diff --git a/src/Options/MailOptions.php b/src/Options/MailOptions.php
index 7da067c..171107b 100644
--- a/src/Options/MailOptions.php
+++ b/src/Options/MailOptions.php
@@ -21,7 +21,7 @@
 class MailOptions extends AbstractOptions
 {
     protected array $eventListeners                = [];
-    protected TransportInterface|string $transport = EsmtpTransport::class;
+    protected TransportInterface|string $transport = SendmailTransport::class;
     protected array $transportMap                  = [
         'esmtp'    => [EsmtpTransport::class],
         'sendmail' => [SendmailTransport::class],
@@ -61,6 +61,9 @@ public function setTransport(string|TransportInterface $transport): void
 
     public function getMessageOptions(): MessageOptions
     {
+        if (! isset($this->messageOptions)) {
+            $this->messageOptions = new MessageOptions();
+        }
         return $this->messageOptions;
     }
 
@@ -71,6 +74,9 @@ public function setMessageOptions(array $messageOptions): void
 
     public function getSmtpOptions(): SmtpOptions
     {
+        if (! isset($this->smtpOptions)) {
+            $this->smtpOptions = new SmtpOptions();
+        }
         return $this->smtpOptions;
     }
 
diff --git a/src/Options/MessageOptions.php b/src/Options/MessageOptions.php
index 4076bad..ad1454f 100644
--- a/src/Options/MessageOptions.php
+++ b/src/Options/MessageOptions.php
@@ -105,6 +105,9 @@ public function setSubject(string $subject): void
 
     public function getBody(): BodyOptions
     {
+        if (! isset($this->body)) {
+            $this->body = new BodyOptions();
+        }
         return $this->body;
     }
 
@@ -115,6 +118,9 @@ public function setBody(array $body): void
 
     public function getAttachments(): AttachmentsOptions
     {
+        if (! isset($this->attachments)) {
+            $this->attachments = new AttachmentsOptions();
+        }
         return $this->attachments;
     }
 
diff --git a/src/Options/SmtpOptions.php b/src/Options/SmtpOptions.php
index be8ccf0..947e74c 100644
--- a/src/Options/SmtpOptions.php
+++ b/src/Options/SmtpOptions.php
@@ -14,22 +14,22 @@
  */
 class SmtpOptions extends AbstractOptions
 {
-    protected string $name            = 'localhost';
+    protected ?string $name           = null;
     protected array $connectionConfig = [];
     protected string $host            = '127.0.0.1';
     protected int $port               = 25;
 
-    protected ?int $connectionTimeLimit;
+    protected ?int $connectionTimeLimit = null;
 
-    public function getName(): string
+    public function getName(): ?string
     {
         return $this->name;
     }
 
     /**
-     * Set the local client hostname or IP
+     * Set the local client hostname or IP; when null, the transport's own default is kept
      */
-    public function setName(string $name): static
+    public function setName(?string $name): static
     {
         $this->name = $name;
         return $this;
diff --git a/src/Result/MailResult.php b/src/Result/MailResult.php
index 07a6028..5de6e9a 100644
--- a/src/Result/MailResult.php
+++ b/src/Result/MailResult.php
@@ -4,7 +4,7 @@
 
 namespace Dot\Mail\Result;
 
-use Exception;
+use Throwable;
 
 class MailResult implements ResultInterface
 {
@@ -12,12 +12,12 @@ class MailResult implements ResultInterface
 
     protected bool $valid;
     protected string $message;
-    protected Exception|null $exception;
+    protected Throwable|null $exception;
 
     public function __construct(
         bool $valid = true,
         string $message = self::DEFAULT_MESSAGE,
-        ?Exception $exception = null
+        ?Throwable $exception = null
     ) {
         $this->valid     = $valid;
         $this->message   = $message;
@@ -36,10 +36,10 @@ public function isValid(): bool
 
     public function hasException(): bool
     {
-        return $this->exception instanceof Exception;
+        return $this->exception instanceof Throwable;
     }
 
-    public function getException(): ?Exception
+    public function getException(): ?Throwable
     {
         return $this->exception;
     }
diff --git a/src/Result/ResultInterface.php b/src/Result/ResultInterface.php
index 9e84413..3d56ebe 100644
--- a/src/Result/ResultInterface.php
+++ b/src/Result/ResultInterface.php
@@ -4,7 +4,7 @@
 
 namespace Dot\Mail\Result;
 
-use Exception;
+use Throwable;
 
 interface ResultInterface
 {
@@ -14,5 +14,5 @@ public function isValid(): bool;
 
     public function hasException(): bool;
 
-    public function getException(): ?Exception;
+    public function getException(): ?Throwable;
 }
diff --git a/src/Service/LogService.php b/src/Service/LogService.php
index 02e4290..890b80d 100644
--- a/src/Service/LogService.php
+++ b/src/Service/LogService.php
@@ -8,14 +8,15 @@
 use Dot\Mail\Email;
 
 use function dirname;
-use function file_exists;
 use function file_put_contents;
+use function is_dir;
 use function json_encode;
 use function mkdir;
 use function sprintf;
 use function trim;
 
 use const FILE_APPEND;
+use const LOCK_EX;
 use const PHP_EOL;
 
 class LogService implements LogServiceInterface
@@ -43,8 +44,8 @@ public function sent(Email $message): false|int|null
          */
         $dirname = dirname($target);
 
-        if (! file_exists($dirname)) {
-            mkdir($dirname, 0755, true);
+        if (! is_dir($dirname) && ! @mkdir($dirname, 0755, true) && ! is_dir($dirname)) {
+            return false;
         }
 
         /**
@@ -63,7 +64,7 @@ public function sent(Email $message): false|int|null
         /**
          * Write the log data and return the result
          */
-        return file_put_contents($target, $data, FILE_APPEND);
+        return file_put_contents($target, $data, FILE_APPEND | LOCK_EX);
     }
 
     public function extractAddresses(array $addressList): array
diff --git a/src/Service/MailService.php b/src/Service/MailService.php
index da943a0..524b971 100644
--- a/src/Service/MailService.php
+++ b/src/Service/MailService.php
@@ -4,6 +4,7 @@
 
 namespace Dot\Mail\Service;
 
+use DirectoryIterator;
 use Dot\Mail\Email;
 use Dot\Mail\Event\MailEvent;
 use Dot\Mail\Event\MailEventListenerAwareInterface;
@@ -12,19 +13,24 @@
 use Dot\Mail\Options\MailOptions;
 use Dot\Mail\Result\MailResult;
 use Dot\Mail\Result\ResultInterface;
-use Exception;
-use Symfony\Component\Mailer\Exception\TransportExceptionInterface;
+use FilesystemIterator;
+use RecursiveDirectoryIterator;
+use RecursiveIteratorIterator;
 use Symfony\Component\Mailer\Transport\TransportInterface;
 use Symfony\Component\Mime\Part\AbstractPart;
 use Symfony\Component\Mime\Part\DataPart;
 use Symfony\Component\Mime\Part\Multipart\MixedPart;
+use Throwable;
 
 use function array_merge;
 use function basename;
 use function count;
-use function fopen;
+use function is_dir;
 use function is_file;
+use function is_readable;
 use function is_string;
+use function sprintf;
+use function str_starts_with;
 
 class MailService implements MailServiceInterface, MailEventListenerAwareInterface
 {
@@ -32,59 +38,81 @@ class MailService implements MailServiceInterface, MailEventListenerAwareInterfa
 
     protected LogServiceInterface $logService;
     protected Email $message;
+    protected Email $prototype;
     protected TransportInterface $transport;
     protected MailOptions $mailOptions;
-    protected array $attachments = [];
+    protected array $attachments        = [];
+    protected array $defaultAttachments = [];
 
+    /**
+     * @param array $attachments The default attachments, restored by reset() after every send
+     */
     public function __construct(
         LogServiceInterface $logService,
         Email $message,
         TransportInterface $transport,
-        MailOptions $mailOptions
+        MailOptions $mailOptions,
+        array $attachments = []
     ) {
-        $this->logService  = $logService;
-        $this->message     = $message;
-        $this->transport   = $transport;
-        $this->mailOptions = $mailOptions;
+        $this->logService         = $logService;
+        $this->message            = $message;
+        $this->prototype          = clone $message;
+        $this->transport          = $transport;
+        $this->mailOptions        = $mailOptions;
+        $this->attachments        = $attachments;
+        $this->defaultAttachments = $attachments;
     }
 
     /**
-     * @throws MailException|TransportExceptionInterface
+     * Sends the current message, then restores the configured defaults (see reset()).
+     * Recipients, subject, body and attachments must be set again for every message.
+     * An exception thrown by a post-send listener propagates unchanged: the message was already delivered.
+     *
+     * @throws MailException
      */
     public function send(): ResultInterface
     {
         $result = new MailResult();
 
-        $this->message->setEncoding('utf-8');
+        if ($this->message->getEncoding() === null) {
+            $this->message->setEncoding(self::DEFAULT_CHARSET);
+        }
+
         try {
             $this->getEventManager()->triggerEvent($this->createMailEvent());
 
             //attach files before sending
             $this->attachFiles();
             $this->getTransport()->send($this->getMessage());
-            $this->getMessage()->setBody(null);
-
-            $this->getEventManager()->triggerEvent($this->createMailEvent(MailEvent::EVENT_MAIL_POST_SEND, $result));
-        } catch (Exception $e) {
+        } catch (Throwable $e) {
             $result = $this->createMailResultFromException($e);
-            //trigger error event
-            $this->getEventManager()->triggerEvent($this->createMailEvent(MailEvent::EVENT_MAIL_SEND_ERROR, $result));
-            throw new MailException($result->getMessage());
-        } finally {
-            // Reset the Symfony Message body after every send attempt (success or failure).
-            // attachFiles() embeds DataParts into Message::$body; without this reset those
-            // DataParts survive a failed send and get wrapped into the next email's body,
-            // causing attachments from a failed send to leak into subsequent emails.
-            $this->getMessage()->setBody(null);
+            try {
+                //trigger error event
+                $this->getEventManager()->triggerEvent(
+                    $this->createMailEvent(MailEvent::EVENT_MAIL_SEND_ERROR, $result)
+                );
+            } finally {
+                $this->reset();
+            }
+            throw new MailException($result->getMessage(), (int) $e->getCode(), $e);
         }
 
-        if ($result->isValid()) {
-            $this->logService->sent($this->getMessage());
+        try {
+            $this->logSent();
+            $this->getEventManager()->triggerEvent($this->createMailEvent(MailEvent::EVENT_MAIL_POST_SEND, $result));
+        } finally {
+            $this->reset();
         }
 
         return $result;
     }
 
+    public function reset(): void
+    {
+        $this->message     = clone $this->prototype;
+        $this->attachments = $this->defaultAttachments;
+    }
+
     public function createMailEvent(
         string $name = MailEvent::EVENT_MAIL_PRE_SEND,
         ?ResultInterface $result = null
@@ -96,26 +124,30 @@ public function createMailEvent(
         return $event;
     }
 
+    /**
+     * @throws MailException When an attachment does not exist or is not readable.
+     */
     public function attachFiles(): false|Email
     {
-        if (count($this->attachments) === 0) {
+        $attachments = array_merge($this->attachments, $this->getDirectoryAttachments());
+        if (count($attachments) === 0) {
             return false;
         }
 
         $body  = $this->message->getBody();
         $parts = [];
 
-        foreach ($this->attachments as $key => $attachment) {
-            if (! is_file($attachment)) {
-                continue;
+        foreach ($attachments as $key => $attachment) {
+            if (! is_file($attachment) || ! is_readable($attachment)) {
+                throw new MailException(
+                    sprintf('Attachment "%s" does not exist or is not readable', $attachment)
+                );
             }
             $basename = is_string($key) ? $key : basename($attachment);
-            $parts[]  = new DataPart(fopen($attachment, 'r'), $basename);
+            $parts[]  = DataPart::fromPath($attachment, $basename);
         }
 
-        if (count($parts) > 0) {
-            $this->message->setBody(new MixedPart($body, ...$parts));
-        }
+        $this->message->setBody(new MixedPart($body, ...$parts));
 
         return $this->message;
     }
@@ -123,13 +155,13 @@ public function attachFiles(): false|Email
     public function setBody(string|AbstractPart $body, ?string $charset = null): void
     {
         if (is_string($body)) {
-            $this->message->html($body);
+            $this->message->html($body, $charset ?? self::DEFAULT_CHARSET);
         } else {
             $this->message->setBody($body);
         }
     }
 
-    public function createMailResultFromException(Exception $e): ResultInterface
+    public function createMailResultFromException(Throwable $e): ResultInterface
     {
         return new MailResult(false, $e->getMessage(), $e);
     }
@@ -177,4 +209,49 @@ public function setTransport(TransportInterface $transport): void
     {
         $this->transport = $transport;
     }
+
+    /**
+     * A failed log write must never turn a delivered email into an error
+     */
+    protected function logSent(): void
+    {
+        try {
+            $this->logService->sent($this->getMessage());
+        } catch (Throwable) {
+            // intentionally ignored
+        }
+    }
+
+    /**
+     * Collects the files of the configured attachments directory at send time.
+     * Relative paths are resolved against the current working directory; dotfiles are skipped.
+     *
+     * @return string[]
+     */
+    protected function getDirectoryAttachments(): array
+    {
+        $dir = $this->mailOptions->getMessageOptions()->getAttachments()->getDir();
+
+        if (($dir['iterate'] ?? false) !== true || ! is_string($dir['path'] ?? null) || ! is_dir($dir['path'])) {
+            return [];
+        }
+
+        $files = ($dir['recursive'] ?? false) === true
+            ? new RecursiveIteratorIterator(
+                new RecursiveDirectoryIterator($dir['path'], FilesystemIterator::SKIP_DOTS),
+                RecursiveIteratorIterator::CHILD_FIRST
+            )
+            : new DirectoryIterator($dir['path']);
+
+        $paths = [];
+        foreach ($files as $fileInfo) {
+            if ($fileInfo->isDir() || str_starts_with($fileInfo->getFilename(), '.')) {
+                continue;
+            }
+
+            $paths[] = $fileInfo->getPathname();
+        }
+
+        return $paths;
+    }
 }
diff --git a/src/Service/MailServiceInterface.php b/src/Service/MailServiceInterface.php
index 5ebf83e..749579f 100644
--- a/src/Service/MailServiceInterface.php
+++ b/src/Service/MailServiceInterface.php
@@ -31,4 +31,10 @@ public function getAttachments(): array;
     public function setAttachments(array $paths): void;
 
     public function setTransport(TransportInterface $transport): void;
+
+    /**
+     * Restores the message and attachments to the configured defaults.
+     * Called automatically after every send() attempt.
+     */
+    public function reset(): void;
 }
diff --git a/test/CommonTrait.php b/test/CommonTrait.php
index e42f8f7..26b831f 100644
--- a/test/CommonTrait.php
+++ b/test/CommonTrait.php
@@ -44,55 +44,57 @@ private function generateConfig(): array
     {
         return [
             'dot_mail' => [
-                'default' => [
-                    'message_options' => [
-                        'from'          => '',
-                        'from_name'     => '',
-                        'reply_to'      => '',
-                        'reply_to_name' => '',
-                        'to'            => [],
-                        'cc'            => [],
-                        'bcc'           => [],
-                        'subject'       => '',
-                        'body'          => [
-                            'content' => '',
-                            'charset' => 'utf-8',
-                        ],
-                        'attachments'   => [
-                            'files' => [],
-                            'dir'   => [
-                                'iterate'   => false,
-                                'path'      => $this->fileSystem->url() . '/data/mail/attachments',
-                                'recursive' => false,
+                'services' => [
+                    'default' => [
+                        'message_options' => [
+                            'from'          => '',
+                            'from_name'     => '',
+                            'reply_to'      => '',
+                            'reply_to_name' => '',
+                            'to'            => [],
+                            'cc'            => [],
+                            'bcc'           => [],
+                            'subject'       => '',
+                            'body'          => [
+                                'content' => '',
+                                'charset' => 'utf-8',
+                            ],
+                            'attachments'   => [
+                                'files' => [],
+                                'dir'   => [
+                                    'iterate'   => false,
+                                    'path'      => $this->fileSystem->url() . '/data/mail/attachments',
+                                    'recursive' => false,
+                                ],
                             ],
                         ],
-                    ],
-                    /**
-                     * the mail transport to use
-                     * can be any class implementing Symfony\Component\Mailer\Transport\TransportInterface
-                     *
-                     * for standard mail transports, you can use these aliases
-                     * - sendmail => Symfony\Component\Mailer\Transport\SendmailTransport
-                     * - esmtp     => Symfony\Component\Mailer\Transport\Smtp\EsmtpTransport
-                     *
-                     * defaults to sendmail
-                     **/
-                    'transport' => 'esmtp',
-                    //options that will be used only if Symfony\Component\Mailer\Transport\Smtp\EsmtpTransport
-                    // adapter is used
-                    'smtp_options' => [
-                        'host'              => 'testHost',
-                        'port'              => 587,
-                        'connection_config' => [
-                            //the smtp authentication identity
-                            'username' => 'test',
-                            //the smtp authentication credential
-                            'password' => 'testPassword',
-                            'tls'      => null,
+                        /**
+                         * the mail transport to use
+                         * can be any class implementing Symfony\Component\Mailer\Transport\TransportInterface
+                         *
+                         * for standard mail transports, you can use these aliases
+                         * - sendmail => Symfony\Component\Mailer\Transport\SendmailTransport
+                         * - esmtp     => Symfony\Component\Mailer\Transport\Smtp\EsmtpTransport
+                         *
+                         * defaults to sendmail
+                         **/
+                        'transport' => 'esmtp',
+                        //options that will be used only if Symfony\Component\Mailer\Transport\Smtp\EsmtpTransport
+                        // adapter is used
+                        'smtp_options' => [
+                            'host'              => 'testHost',
+                            'port'              => 587,
+                            'connection_config' => [
+                                //the smtp authentication identity
+                                'username' => 'test',
+                                //the smtp authentication credential
+                                'password' => 'testPassword',
+                                'tls'      => null,
+                            ],
                         ],
                     ],
+                    'test'    => 'string test',
                 ],
-                'test'    => 'string test',
                 // option to log the SENT emails
                 'log' => [
                     'sent' => $this->fileSystem->url() . '/log/mail/sent.log',
diff --git a/test/ConfigProviderTest.php b/test/ConfigProviderTest.php
index cb4a0b8..8d7d4ce 100644
--- a/test/ConfigProviderTest.php
+++ b/test/ConfigProviderTest.php
@@ -10,6 +10,7 @@
 use Dot\Mail\Factory\MailServiceAbstractFactory;
 use Dot\Mail\Service\LogService;
 use Dot\Mail\Service\LogServiceInterface;
+use Dot\Mail\Service\MailServiceInterface;
 use PHPUnit\Framework\TestCase;
 
 class ConfigProviderTest extends TestCase
@@ -42,6 +43,10 @@ public function testDependenciesHasAliases(): void
             LogService::class,
             $this->config['dependencies']['aliases'][LogServiceInterface::class]
         );
+        $this->assertSame(
+            'dot-mail.service.default',
+            $this->config['dependencies']['aliases'][MailServiceInterface::class]
+        );
     }
 
     public function testDependenciesHasAbstractFactories(): void
diff --git a/test/EmailTest.php b/test/EmailTest.php
index 3d4f871..5af708c 100644
--- a/test/EmailTest.php
+++ b/test/EmailTest.php
@@ -9,6 +9,8 @@
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\Mime\Address;
 use Symfony\Component\Mime\Exception\LogicException;
+use Symfony\Component\Mime\Part\Multipart\AlternativePart;
+use Symfony\Component\Mime\Part\TextPart;
 
 class EmailTest extends TestCase
 {
@@ -85,4 +87,34 @@ public function testAddressObjectsInArraysAreKept(): void
         $this->assertCount(1, $cc);
         $this->assertSame('Copy', $cc[0]->getName());
     }
+
+    public function testTextOnlyMessageHasOnlyTextPart(): void
+    {
+        $subject = new Email();
+        $subject->text('plain text');
+
+        $body = $subject->getBody();
+        $this->assertSame(TextPart::class, $body::class);
+        $this->assertSame('plain text', $body->getBody());
+    }
+
+    public function testTextAndHtmlMessageIsAlternative(): void
+    {
+        $subject = new Email();
+        $subject->text('plain text');
+        $subject->html('<p>html</p>');
+
+        $this->assertInstanceOf(AlternativePart::class, $subject->getBody());
+    }
+
+    public function testMessageWithoutBodyIsInvalid(): void
+    {
+        $subject = new Email();
+        $subject->setFrom('from@example.com');
+        $subject->setTo('to@example.com');
+
+        $this->expectException(LogicException::class);
+        $this->expectExceptionMessage('A message must have a text or an HTML part.');
+        $subject->ensureValidity();
+    }
 }
diff --git a/test/Event/MailEventTest.php b/test/Event/MailEventTest.php
index d6323be..171191b 100644
--- a/test/Event/MailEventTest.php
+++ b/test/Event/MailEventTest.php
@@ -5,6 +5,7 @@
 namespace DotTest\Mail\Event;
 
 use Dot\Mail\Event\MailEvent;
+use Dot\Mail\Result\MailResult;
 use Dot\Mail\Service\MailServiceInterface;
 use PHPUnit\Framework\MockObject\Exception;
 use PHPUnit\Framework\MockObject\MockObject;
@@ -48,4 +49,14 @@ public function testEventPropagation(): void
         $event->stopPropagation();
         $this->assertTrue($event->propagationIsStopped());
     }
+
+    public function testResultIsNullUntilSet(): void
+    {
+        $event = new MailEvent($this->mailService);
+        $this->assertNull($event->getResult());
+
+        $result = new MailResult();
+        $event->setResult($result);
+        $this->assertSame($result, $event->getResult());
+    }
 }
diff --git a/test/Factory/AbstractMailFactoryTest.php b/test/Factory/AbstractMailFactoryTest.php
index 319a6b5..dc958d2 100644
--- a/test/Factory/AbstractMailFactoryTest.php
+++ b/test/Factory/AbstractMailFactoryTest.php
@@ -4,6 +4,7 @@
 
 namespace DotTest\Mail\Factory;
 
+use Dot\Mail\Exception\InvalidArgumentException;
 use Dot\Mail\Factory\AbstractMailFactory;
 use Dot\Mail\Options\MailOptions;
 use DotTest\Mail\CommonTrait;
@@ -102,4 +103,72 @@ public function testWillNotCreateRequestedNameWithoutParts(): void
             restore_error_handler();
         }
     }
+
+    /**
+     * @throws Exception
+     * @throws ContainerExceptionInterface
+     * @throws NotFoundExceptionInterface
+     */
+    public function testLogKeyIsNotACreatableService(): void
+    {
+        $container = $this->createMock(ContainerInterface::class);
+        $container->method('get')->willReturn($this->config);
+
+        $this->assertTrue($this->subject->canCreate($container, 'dot-mail.testPart.default'));
+        $this->assertFalse($this->subject->canCreate($container, 'dot-mail.testPart.log'));
+    }
+
+    /**
+     * @throws Exception
+     * @throws ContainerExceptionInterface
+     * @throws NotFoundExceptionInterface
+     */
+    public function testServicesCanOnlyComeFromServicesKey(): void
+    {
+        $container = $this->createMock(ContainerInterface::class);
+        $container->method('get')->willReturn([
+            'dot_mail' => [
+                'log'      => ['sent' => '/tmp/sent.log'],
+                'services' => ['log' => [], 'other' => []],
+            ],
+        ]);
+
+        $this->assertTrue($this->subject->canCreate($container, 'dot-mail.testPart.other'));
+        $this->assertTrue($this->subject->canCreate($container, 'dot-mail.testPart.log'));
+        $this->assertFalse($this->subject->canCreate($container, 'dot-mail.testPart.missing'));
+    }
+
+    /**
+     * @throws Exception
+     * @throws ContainerExceptionInterface
+     * @throws NotFoundExceptionInterface
+     */
+    public function testOldConfigurationLayoutIsRejected(): void
+    {
+        $container = $this->createMock(ContainerInterface::class);
+        $container->method('get')->willReturn([
+            'dot_mail' => [
+                'default' => ['transport' => 'sendmail'],
+                'log'     => ['sent' => '/tmp/sent.log'],
+            ],
+        ]);
+
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Mail service "default" must be configured under "dot_mail.services"');
+        $this->subject->canCreate($container, 'dot-mail.testPart.default');
+    }
+
+    /**
+     * @throws Exception
+     * @throws ContainerExceptionInterface
+     * @throws NotFoundExceptionInterface
+     */
+    public function testConfigurationWithOnlyLogCreatesNoService(): void
+    {
+        $container = $this->createMock(ContainerInterface::class);
+        $container->method('get')->willReturn(['dot_mail' => ['log' => ['sent' => '/tmp/sent.log']]]);
+
+        $this->assertFalse($this->subject->canCreate($container, 'dot-mail.testPart.log'));
+        $this->assertFalse($this->subject->canCreate($container, 'dot-mail.testPart.default'));
+    }
 }
diff --git a/test/Factory/MailServiceAbstractFactoryTest.php b/test/Factory/MailServiceAbstractFactoryTest.php
index 0519efb..bf62743 100644
--- a/test/Factory/MailServiceAbstractFactoryTest.php
+++ b/test/Factory/MailServiceAbstractFactoryTest.php
@@ -16,6 +16,7 @@
 use Dot\Mail\Service\LogServiceInterface;
 use Dot\Mail\Service\MailService;
 use DotTest\Mail\CommonTrait;
+use ErrorException;
 use org\bovigo\vfs\vfsStream;
 use PHPUnit\Framework\MockObject\Exception;
 use PHPUnit\Framework\MockObject\MockObject;
@@ -23,7 +24,12 @@
 use Psr\Container\ContainerExceptionInterface;
 use Psr\Container\ContainerInterface;
 use Psr\Container\NotFoundExceptionInterface;
+use Symfony\Component\Mailer\Transport\SendmailTransport;
 use Symfony\Component\Mailer\Transport\Smtp\EsmtpTransport;
+use Symfony\Component\Mailer\Transport\Smtp\Stream\SocketStream;
+
+use function restore_error_handler;
+use function set_error_handler;
 
 class MailServiceAbstractFactoryTest extends TestCase
 {
@@ -119,10 +125,6 @@ public function testGenerateServiceWithProvidedAdapter(): void
                 'tls'      => null,
             ]);
 
-        $this->smtpOptions->expects($this->once())
-            ->method('getHost')
-            ->willReturn('localhost');
-
         $this->mailOptions->expects($this->any())
             ->method('getSmtpOptions')
             ->willReturn($this->smtpOptions);
@@ -187,10 +189,6 @@ public function testGenerateServiceWithoutProvidedAdapter(): void
                 'tls'      => false,
             ]);
 
-        $this->smtpOptions->expects($this->once())
-            ->method('getHost')
-            ->willReturn('localhost');
-
         $this->mailOptions->expects($this->any())
             ->method('getSmtpOptions')
             ->willReturn($this->smtpOptions);
@@ -262,4 +260,229 @@ public function testGenerateServiceThrowException(): void
         $this->expectException(InvalidArgumentException::class);
         ($this->subject)($this->container, $requestedName);
     }
+
+    /**
+     * @throws ContainerExceptionInterface
+     * @throws Exception
+     * @throws NotFoundExceptionInterface
+     */
+    public function testGenerateServiceFromMinimalConfiguration(): void
+    {
+        $container = $this->createMock(ContainerInterface::class);
+        $container->method('get')->willReturnMap([
+            ['dot-mail.options.default', new MailOptions([])],
+            [LogServiceInterface::class, $this->createMock(LogService::class)],
+        ]);
+
+        $mailService = ($this->subject)($container, 'dot-mail.service.default');
+
+        $this->assertInstanceOf(MailService::class, $mailService);
+        $this->assertInstanceOf(SendmailTransport::class, $mailService->getTransport());
+        $this->assertNull($mailService->getMessage()->getHtmlBody());
+        $this->assertSame([], $mailService->getAttachments());
+    }
+
+    /**
+     * @throws ContainerExceptionInterface
+     * @throws Exception
+     * @throws NotFoundExceptionInterface
+     */
+    public function testGenerateServiceWithBodyContent(): void
+    {
+        $options = new MailOptions([
+            'transport'       => 'sendmail',
+            'message_options' => ['body' => ['content' => '<p>Hello</p>', 'charset' => 'iso-8859-1']],
+        ]);
+
+        $container = $this->createMock(ContainerInterface::class);
+        $container->method('get')->willReturnMap([
+            ['dot-mail.options.default', $options],
+            [LogServiceInterface::class, $this->createMock(LogService::class)],
+        ]);
+
+        $mailService = ($this->subject)($container, 'dot-mail.service.default');
+
+        $this->assertSame('<p>Hello</p>', $mailService->getMessage()->getHtmlBody());
+        $this->assertSame('iso-8859-1', $mailService->getMessage()->getHtmlCharset());
+    }
+
+    /**
+     * @throws ContainerExceptionInterface
+     * @throws Exception
+     * @throws NotFoundExceptionInterface
+     */
+    public function testEsmtpTransportWithoutConnectionConfigKeys(): void
+    {
+        $options = new MailOptions([
+            'transport'    => 'esmtp',
+            'smtp_options' => ['host' => 'localhost', 'port' => 587],
+        ]);
+
+        $container = $this->createMock(ContainerInterface::class);
+        $container->method('get')->willReturnMap([
+            ['dot-mail.options.default', $options],
+            [LogServiceInterface::class, $this->createMock(LogService::class)],
+        ]);
+
+        set_error_handler(static function (int $severity, string $message): never {
+            throw new ErrorException($message, 0, $severity);
+        });
+
+        try {
+            $transport = ($this->subject)($container, 'dot-mail.service.default')->getTransport();
+        } finally {
+            restore_error_handler();
+        }
+
+        $this->assertInstanceOf(EsmtpTransport::class, $transport);
+        $this->assertSame('', $transport->getUsername());
+    }
+
+    /**
+     * @throws ContainerExceptionInterface
+     * @throws Exception
+     * @throws NotFoundExceptionInterface
+     */
+    public function testEsmtpCredentialsWithSpecialCharacters(): void
+    {
+        $options = new MailOptions([
+            'transport'    => 'esmtp',
+            'smtp_options' => [
+                'host'              => 'localhost',
+                'port'              => 587,
+                'connection_config' => ['username' => 'user@example.com', 'password' => 'p:ss/w@rd'],
+            ],
+        ]);
+
+        $container = $this->createMock(ContainerInterface::class);
+        $container->method('get')->willReturnMap([
+            ['dot-mail.options.default', $options],
+            [LogServiceInterface::class, $this->createMock(LogService::class)],
+        ]);
+
+        $transport = ($this->subject)($container, 'dot-mail.service.default')->getTransport();
+
+        $this->assertInstanceOf(EsmtpTransport::class, $transport);
+        $this->assertSame('user@example.com', $transport->getUsername());
+        $this->assertSame('p:ss/w@rd', $transport->getPassword());
+    }
+
+    /**
+     * @throws ContainerExceptionInterface
+     * @throws Exception
+     * @throws NotFoundExceptionInterface
+     */
+    public function testEsmtpTransportConfiguration(): void
+    {
+        $options = new MailOptions([
+            'transport'    => 'esmtp',
+            'smtp_options' => [
+                'host'                  => 'mail.example.com',
+                'port'                  => 2525,
+                'name'                  => 'client.example.com',
+                'connection_time_limit' => 7,
+                'connection_config'     => ['username' => 'user', 'password' => 'secret'],
+            ],
+        ]);
+
+        $transport = ($this->subject)($this->containerFor($options), 'dot-mail.service.default')->getTransport();
+
+        $this->assertInstanceOf(EsmtpTransport::class, $transport);
+        $this->assertSame('client.example.com', $transport->getLocalDomain());
+        $stream = $transport->getStream();
+        $this->assertInstanceOf(SocketStream::class, $stream);
+        $this->assertSame(7.0, $stream->getTimeout());
+        $this->assertTrue($transport->isAutoTls());
+    }
+
+    /**
+     * @throws ContainerExceptionInterface
+     * @throws Exception
+     * @throws NotFoundExceptionInterface
+     */
+    public function testEsmtpTlsSettings(): void
+    {
+        $cases = [
+            'automatic on 587' => [587, null, true, false],
+            'implicit on 465'  => [465, null, true, true],
+            'disabled'         => [587, false, false, false],
+        ];
+
+        foreach ($cases as $label => [$port, $tls, $autoTls, $implicitTls]) {
+            $options = new MailOptions([
+                'transport'    => 'esmtp',
+                'smtp_options' => [
+                    'host'              => 'mail.example.com',
+                    'port'              => $port,
+                    'connection_config' => ['tls' => $tls],
+                ],
+            ]);
+
+            $transport = ($this->subject)($this->containerFor($options), 'dot-mail.service.default')->getTransport();
+
+            $this->assertInstanceOf(EsmtpTransport::class, $transport);
+            $this->assertSame($autoTls, $transport->isAutoTls(), $label);
+            $this->assertInstanceOf(SocketStream::class, $transport->getStream());
+            $this->assertSame($implicitTls, $transport->getStream()->isTLS(), $label);
+        }
+    }
+
+    /**
+     * @throws ContainerExceptionInterface
+     * @throws Exception
+     * @throws NotFoundExceptionInterface
+     */
+    public function testProvidedTransportObjectIsUsedAsGiven(): void
+    {
+        $provided = new EsmtpTransport('provided.example.com', 25, false);
+        $options  = new MailOptions([
+            'transport'    => $provided,
+            'smtp_options' => ['host' => 'ignored.example.com', 'port' => 587],
+        ]);
+
+        $transport = ($this->subject)($this->containerFor($options), 'dot-mail.service.default')->getTransport();
+
+        $this->assertSame($provided, $transport);
+    }
+
+    /**
+     * @throws ContainerExceptionInterface
+     * @throws Exception
+     * @throws NotFoundExceptionInterface
+     */
+    public function testServiceKeepsConfiguredDefaultsAfterReset(): void
+    {
+        $options = new MailOptions([
+            'transport'       => 'sendmail',
+            'message_options' => [
+                'from'        => 'from@example.com',
+                'subject'     => 'Default subject',
+                'body'        => ['content' => '<p>Default</p>'],
+                'attachments' => ['files' => ['/some/default/file.txt']],
+            ],
+        ]);
+
+        $mailService = ($this->subject)($this->containerFor($options), 'dot-mail.service.default');
+        $mailService->getMessage()->addTo('someone@example.com');
+        $mailService->addAttachment('/another/file.txt');
+
+        $mailService->reset();
+
+        $this->assertSame('Default subject', $mailService->getMessage()->getSubject());
+        $this->assertSame('<p>Default</p>', $mailService->getMessage()->getHtmlBody());
+        $this->assertSame('from@example.com', $mailService->getMessage()->getFrom()[0]->getAddress());
+        $this->assertSame([], $mailService->getMessage()->getTo());
+        $this->assertSame(['/some/default/file.txt'], $mailService->getAttachments());
+    }
+
+    private function containerFor(MailOptions $options): ContainerInterface
+    {
+        $container = $this->createMock(ContainerInterface::class);
+        $container->method('get')->willReturnMap([
+            ['dot-mail.options.default', $options],
+            [LogServiceInterface::class, $this->createMock(LogService::class)],
+        ]);
+
+        return $container;
+    }
 }
diff --git a/test/Options/MailOptionsTest.php b/test/Options/MailOptionsTest.php
index ab427c7..29de436 100644
--- a/test/Options/MailOptionsTest.php
+++ b/test/Options/MailOptionsTest.php
@@ -50,4 +50,14 @@ public function testTransportAliasIsCaseInsensitive(): void
         $subject->setTransport('Custom\\Transport');
         $this->assertSame('Custom\\Transport', $subject->getTransport());
     }
+
+    public function testDefaultsWithoutConfiguration(): void
+    {
+        $subject = new MailOptions();
+
+        $this->assertSame(SendmailTransport::class, $subject->getTransport());
+        $this->assertContainsOnlyInstancesOf(MessageOptions::class, [$subject->getMessageOptions()]);
+        $this->assertContainsOnlyInstancesOf(SmtpOptions::class, [$subject->getSmtpOptions()]);
+        $this->assertSame($subject->getMessageOptions(), $subject->getMessageOptions());
+    }
 }
diff --git a/test/Options/MessageOptionsTest.php b/test/Options/MessageOptionsTest.php
index 7a68400..42d31a5 100644
--- a/test/Options/MessageOptionsTest.php
+++ b/test/Options/MessageOptionsTest.php
@@ -48,4 +48,14 @@ public function testGettersAndSetters(): void
         $this->assertContainsOnlyInstancesOf(BodyOptions::class, [$subject->getBody()]);
         $this->assertContainsOnlyInstancesOf(AttachmentsOptions::class, [$subject->getAttachments()]);
     }
+
+    public function testDefaultsWithoutConfiguration(): void
+    {
+        $subject = new MessageOptions();
+
+        $this->assertContainsOnlyInstancesOf(BodyOptions::class, [$subject->getBody()]);
+        $this->assertSame('', $subject->getBody()->getContent());
+        $this->assertContainsOnlyInstancesOf(AttachmentsOptions::class, [$subject->getAttachments()]);
+        $this->assertSame([], $subject->getAttachments()->getFiles());
+    }
 }
diff --git a/test/Options/SmtpOptionsTest.php b/test/Options/SmtpOptionsTest.php
index 81cdc08..d24e155 100644
--- a/test/Options/SmtpOptionsTest.php
+++ b/test/Options/SmtpOptionsTest.php
@@ -41,4 +41,9 @@ public function testPortBoundaries(): void
         $this->expectExceptionMessage('Port must be greater than 0; received "0"');
         $subject->setPort(0);
     }
+
+    public function testConnectionTimeLimitDefaultsToNull(): void
+    {
+        $this->assertNull((new SmtpOptions())->getConnectionTimeLimit());
+    }
 }
diff --git a/test/Result/MailResultTest.php b/test/Result/MailResultTest.php
index 94c90bf..e5e44b0 100644
--- a/test/Result/MailResultTest.php
+++ b/test/Result/MailResultTest.php
@@ -7,6 +7,7 @@
 use Dot\Mail\Result\MailResult;
 use Exception;
 use PHPUnit\Framework\TestCase;
+use TypeError;
 
 class MailResultTest extends TestCase
 {
@@ -27,4 +28,14 @@ public function testGettersAndSetters(): void
         $this->assertSame($exception->getMessage(), $mailResult->getException()->getMessage());
         $this->assertTrue($mailResult->hasException());
     }
+
+    public function testResultCanHoldAnyThrowable(): void
+    {
+        $error = new TypeError('Type error test');
+
+        $mailResult = new MailResult(false, $error->getMessage(), $error);
+
+        $this->assertTrue($mailResult->hasException());
+        $this->assertSame($error, $mailResult->getException());
+    }
 }
diff --git a/test/Service/LogServiceTest.php b/test/Service/LogServiceTest.php
index e2bfe79..8692d20 100644
--- a/test/Service/LogServiceTest.php
+++ b/test/Service/LogServiceTest.php
@@ -83,4 +83,24 @@ public function testSentMailIsLogged(): void
             file_get_contents($this->fileSystem->url() . '/log/mail/sent.log')
         );
     }
+
+    /**
+     * @throws Exception
+     */
+    public function testSentReturnsFalseWhenLogDirectoryCannotBeCreated(): void
+    {
+        // the "directory" of the target is an existing file, so it can be neither used nor created
+        $target     = $this->fileSystem->url() . '/data/mail/attachments/testPdfAttachment.pdf/sent.log';
+        $logService = new LogService(['log' => ['sent' => $target]]);
+        $message    = $this->createMock(Email::class);
+
+        $this->assertFalse($logService->sent($message));
+    }
+
+    public function testSentIsDisabledWithoutTarget(): void
+    {
+        $logService = new LogService(['log' => ['sent' => null]]);
+
+        $this->assertNull($logService->sent(new Email()));
+    }
 }
diff --git a/test/Service/MailServiceTest.php b/test/Service/MailServiceTest.php
index 685711f..22f4ae6 100644
--- a/test/Service/MailServiceTest.php
+++ b/test/Service/MailServiceTest.php
@@ -5,6 +5,7 @@
 namespace DotTest\Mail\Service;
 
 use Dot\Mail\Email;
+use Dot\Mail\Event\AbstractMailEventListener;
 use Dot\Mail\Event\MailEvent;
 use Dot\Mail\Exception\MailException;
 use Dot\Mail\Exception\RuntimeException;
@@ -25,6 +26,12 @@
 use Symfony\Component\Mime\Part\DataPart;
 use Symfony\Component\Mime\Part\Multipart\MixedPart;
 use Symfony\Component\Mime\Part\TextPart;
+use Throwable;
+use TypeError;
+
+use function file_put_contents;
+use function mkdir;
+use function sort;
 
 class MailServiceTest extends TestCase
 {
@@ -209,23 +216,18 @@ public function testAttachFilesSingleAttachmentIsFlat(): void
         $this->assertInstanceOf(DataPart::class, $parts[1]);
     }
 
-    public function testAttachFilesSkipsNonExistentFiles(): void
+    public function testAttachFilesThrowsOnMissingFile(): void
     {
         $this->message->html('<p>Test</p>');
 
-        $this->mailService->addAttachment('/nonexistent/file.pdf');
         $this->mailService->addAttachment(
             $this->fileSystem->url() . '/data/mail/attachments/testPdfAttachment.pdf'
         );
+        $this->mailService->addAttachment('/nonexistent/file.pdf');
 
+        $this->expectException(MailException::class);
+        $this->expectExceptionMessage('Attachment "/nonexistent/file.pdf" does not exist or is not readable');
         $this->mailService->attachFiles();
-
-        $body = $this->message->getBody();
-        $this->assertInstanceOf(MixedPart::class, $body);
-
-        $parts = $body->getParts();
-        // only 1 valid attachment + the html body
-        $this->assertCount(2, $parts);
     }
 
     public function testAttachFilesPreservesCustomFilename(): void
@@ -299,11 +301,10 @@ public function testAttachFilesNoNestedMixedParts(): void
     /**
      * Found an attachment leak where DataParts
      * embedded into Message::$body by attachFiles() survived a failed send
-     * and were wrapped into the next email. The fix must live in dot-mail:
-     * after send() (success OR failure) the underlying Message::$body must
-     * be reset so the next send rebuilds the body from scratch.
+     * and were wrapped into the next email. After send() (success OR failure)
+     * the service must hand out a clean message built from the configured defaults.
      */
-    public function testMessageBodyIsResetAfterFailedSendToPreventAttachmentLeak(): void
+    public function testMessageIsResetAfterFailedSendToPreventAttachmentLeak(): void
     {
         $this->mailService->setSubject('First');
         $this->message->html('First body');
@@ -322,11 +323,12 @@ public function testMessageBodyIsResetAfterFailedSendToPreventAttachmentLeak():
             // expected
         }
 
+        $this->assertNotSame($this->message, $this->mailService->getMessage());
         $this->assertNull(
-            $this->readPrivateMessageBody($this->message),
-            'After a failed send the Symfony Message::$body must be reset; '
-            . 'otherwise attachFiles() will wrap the leaked MixedPart into the next email.'
+            $this->readPrivateMessageBody($this->mailService->getMessage()),
+            'After a failed send the message must be rebuilt from the defaults, without the attached body.'
         );
+        $this->assertSame([], $this->mailService->getAttachments());
     }
 
     /**
@@ -362,10 +364,9 @@ public function testAttachmentsDoNotLeakIntoSubsequentSendAfterFailure(): void
             // expected
         }
 
-        // Reconfigure: brand new email with NO attachments.
-        $this->mailService->setAttachments([]);
+        // Configure a brand new email; the attachment of the first one must be gone.
         $this->mailService->setSubject('Second');
-        $this->message->html('Second email - must not carry first email\'s attachment');
+        $this->mailService->getMessage()->html('Second email - must not carry first email\'s attachment');
 
         $this->mailService->send();
 
@@ -381,13 +382,14 @@ public function testAttachmentsDoNotLeakIntoSubsequentSendAfterFailure(): void
     }
 
     /**
-     * Confirms the success path also resets the body, so a future refactor
+     * Confirms the success path also resets the message, so a future refactor
      * does not silently regress the success case.
      */
-    public function testMessageBodyIsResetAfterSuccessfulSend(): void
+    public function testMessageIsResetAfterSuccessfulSend(): void
     {
         $this->mailService->setSubject('Hello');
         $this->message->html('Body');
+        $this->message->addTo('first@example.com');
         $this->mailService->addAttachment(
             $this->fileSystem->url() . '/data/mail/attachments/testPdfAttachment.pdf'
         );
@@ -396,17 +398,200 @@ public function testMessageBodyIsResetAfterSuccessfulSend(): void
 
         $this->mailService->send();
 
-        $this->assertNull(
-            $this->readPrivateMessageBody($this->message),
-            'Message body should be null after a successful send so the next email starts clean.'
+        $message = $this->mailService->getMessage();
+        $this->assertNotSame($this->message, $message);
+        $this->assertNull($this->readPrivateMessageBody($message));
+        $this->assertNull($message->getSubject());
+        $this->assertSame([], $message->getTo());
+        $this->assertSame([], $this->mailService->getAttachments());
+    }
+
+    public function testResetRestoresConfiguredDefaults(): void
+    {
+        $defaults = new Email();
+        $defaults->subject('Default subject');
+        $defaults->addFrom('from@example.com');
+
+        $mailService = new MailService(
+            $this->createMock(LogServiceInterface::class),
+            $defaults,
+            $this->transportInterface,
+            $this->createMock(MailOptions::class),
+            ['/default/attachment.txt']
+        );
+
+        $mailService->setSubject('Changed');
+        $mailService->getMessage()->addTo('someone@example.com');
+        $mailService->addAttachment('/extra/attachment.txt');
+
+        $mailService->reset();
+
+        $this->assertSame('Default subject', $mailService->getMessage()->getSubject());
+        $this->assertSame('from@example.com', $mailService->getMessage()->getFrom()[0]->getAddress());
+        $this->assertSame([], $mailService->getMessage()->getTo());
+        $this->assertSame(['/default/attachment.txt'], $mailService->getAttachments());
+    }
+
+    public function testListenersSeeTheFullMessageBeforeTheReset(): void
+    {
+        $listener = new class extends AbstractMailEventListener {
+            public array $seen = [];
+
+            public function onPostSend(MailEvent $e): void
+            {
+                $this->seen[] = $e->getMailService()->getMessage()->getSubject();
+            }
+        };
+        $this->mailService->attachListener($listener);
+        $this->mailService->setSubject('Visible to listeners');
+
+        $this->mailService->send();
+
+        $this->assertSame(['Visible to listeners'], $listener->seen);
+        $this->assertNull($this->mailService->getMessage()->getSubject());
+    }
+
+    public function testSendFailureKeepsThePreviousException(): void
+    {
+        $exception = new RuntimeException('Transport failure', 42);
+        $this->transportInterface->method('send')->willThrowException($exception);
+
+        try {
+            $this->mailService->send();
+            $this->fail('Expected MailException was not thrown');
+        } catch (MailException $e) {
+            $this->assertSame($exception, $e->getPrevious());
+            $this->assertSame(42, $e->getCode());
+            $this->assertSame('Transport failure', $e->getMessage());
+        }
+    }
+
+    public function testErrorsAreReportedAsSendErrors(): void
+    {
+        $listener = new class extends AbstractMailEventListener {
+            public array $events = [];
+
+            public function onSendError(MailEvent $e): void
+            {
+                $this->events[] = $e->getResult()?->getException()::class;
+            }
+        };
+        $this->mailService->attachListener($listener);
+        $this->transportInterface->method('send')->willThrowException(new TypeError('Type problem'));
+
+        try {
+            $this->mailService->send();
+            $this->fail('Expected MailException was not thrown');
+        } catch (MailException $e) {
+            $this->assertInstanceOf(TypeError::class, $e->getPrevious());
+        }
+
+        $this->assertSame([TypeError::class], $listener->events);
+    }
+
+    public function testFailingPostSendListenerIsNotReportedAsSendError(): void
+    {
+        $listener = new class extends AbstractMailEventListener {
+            public int $errors = 0;
+
+            public function onPostSend(MailEvent $e): void
+            {
+                throw new RuntimeException('Listener failure');
+            }
+
+            public function onSendError(MailEvent $e): void
+            {
+                $this->errors++;
+            }
+        };
+        $this->mailService->attachListener($listener);
+        $this->mailService->setSubject('Delivered');
+
+        $caught = null;
+        try {
+            $this->mailService->send();
+        } catch (Throwable $e) {
+            $caught = $e;
+        }
+
+        $this->assertInstanceOf(RuntimeException::class, $caught);
+        $this->assertSame('Listener failure', $caught->getMessage());
+        $this->assertSame(0, $listener->errors);
+        $this->assertNull($this->mailService->getMessage()->getSubject(), 'The message must be reset anyway');
+    }
+
+    public function testDirectoryAttachmentsAreCollectedAtSendTime(): void
+    {
+        $dir = $this->fileSystem->url() . '/data/mail/attachments';
+        file_put_contents($dir . '/.gitkeep', '');
+        mkdir($dir . '/nested');
+        file_put_contents($dir . '/nested/nested.txt', 'nested');
+
+        $options = new MailOptions([
+            'message_options' => [
+                'attachments' => ['dir' => ['iterate' => true, 'path' => $dir, 'recursive' => false]],
+            ],
+        ]);
+
+        $message     = new Email();
+        $mailService = new MailService(
+            $this->createMock(LogServiceInterface::class),
+            $message,
+            $this->transportInterface,
+            $options
         );
+        $message->html('<p>Test</p>');
+
+        // added after the service was created
+        file_put_contents($dir . '/late.txt', 'late');
+
+        $mailService->attachFiles();
+
+        $body = $message->getBody();
+        $this->assertInstanceOf(MixedPart::class, $body);
+        $names = [];
+        foreach ($body->getParts() as $part) {
+            if ($part instanceof DataPart) {
+                $names[] = $part->getFilename();
+            }
+        }
+        sort($names);
+
+        $this->assertSame(['late.txt', 'testPdfAttachment.pdf', 'testXlsAttachment.xls'], $names);
+    }
+
+    public function testRecursiveDirectoryAttachments(): void
+    {
+        $dir = $this->fileSystem->url() . '/data/mail/attachments';
+        mkdir($dir . '/nested');
+        file_put_contents($dir . '/nested/nested.txt', 'nested');
+
+        $options = new MailOptions([
+            'message_options' => [
+                'attachments' => ['dir' => ['iterate' => true, 'path' => $dir, 'recursive' => true]],
+            ],
+        ]);
+
+        $message     = new Email();
+        $mailService = new MailService(
+            $this->createMock(LogServiceInterface::class),
+            $message,
+            $this->transportInterface,
+            $options
+        );
+        $message->html('<p>Test</p>');
+
+        $mailService->attachFiles();
+
+        $body = $message->getBody();
+        $this->assertInstanceOf(MixedPart::class, $body);
+        $this->assertCount(4, $body->getParts());
     }
 
     private function readPrivateMessageBody(Message $message): ?AbstractPart
     {
         $reflection = new ReflectionClass(Message::class);
         $property   = $reflection->getProperty('body');
-        $property->setAccessible(true);
 
         return $property->getValue($message);
     }
@@ -427,4 +612,73 @@ private function bodyContainsDataPart(AbstractPart $part): bool
 
         return false;
     }
+
+    public function testSetBodyUsesProvidedCharset(): void
+    {
+        $this->mailService->setBody('<p>Body</p>', 'iso-8859-1');
+
+        $this->assertSame('iso-8859-1', $this->message->getHtmlCharset());
+    }
+
+    public function testSetBodyDefaultsToUtf8(): void
+    {
+        $this->mailService->setBody('<p>Body</p>');
+
+        $this->assertSame('utf-8', $this->message->getHtmlCharset());
+    }
+
+    public function testSendKeepsConfiguredEncoding(): void
+    {
+        $encoding = null;
+        $this->transportInterface->method('send')->willReturnCallback(
+            function (Email $email) use (&$encoding) {
+                $encoding = $email->getEncoding();
+                return null;
+            }
+        );
+
+        $this->mailService->setBody('<p>Body</p>', 'iso-8859-1');
+        $this->mailService->send();
+
+        $this->assertSame('iso-8859-1', $encoding);
+    }
+
+    public function testSendSetsDefaultEncodingWhenNoneIsSet(): void
+    {
+        $encoding = 'not called';
+        $this->transportInterface->method('send')->willReturnCallback(
+            function (Email $email) use (&$encoding) {
+                $encoding = $email->getEncoding();
+                return null;
+            }
+        );
+
+        $this->assertNull($this->message->getEncoding());
+
+        $this->mailService->send();
+
+        $this->assertSame('utf-8', $encoding);
+    }
+
+    /**
+     * @throws Exception
+     */
+    public function testLogFailureDoesNotBreakSuccessfulSend(): void
+    {
+        $logService = $this->createMock(LogServiceInterface::class);
+        $logService->expects($this->once())
+            ->method('sent')
+            ->willThrowException(new RuntimeException('Log failure'));
+
+        $mailService = new MailService(
+            $logService,
+            new Email(),
+            $this->transportInterface,
+            $this->createMock(MailOptions::class)
+        );
+
+        $result = $mailService->send();
+
+        $this->assertTrue($result->isValid());
+    }
 }