log4j auto configuration docs

docs/platforms/java/guides/spring-boot/logging-frameworks/log4j2.mdx

@@ -13,7 +13,9 @@ By default this integration captures logs as breadcrumbs and error events (great
 
 ## Installation
 
-To use Sentry's Log4j 2 integration in Spring Boot application, you must include a dependency to the `sentry-log4j2` module:
+Spring Boot uses Logback by default, so first [follow the guide on configuring Log4j 2 with Spring Boot](https://docs.spring.io/spring-boot/how-to/logging.html#howto.logging.log4j) to make Log4j 2 the active logging backend.
+
+Then, to use Sentry's Log4j 2 integration in your Spring Boot application, you must include a dependency to the `sentry-log4j2` module:
 
 ```xml {tabTitle:Maven}
 <dependency>
@@ -43,9 +45,40 @@ To send logs to Sentry and have them show up in the Logs section, you need to en
 sentry.logs.enabled=true
 ```
 
+For Spring Boot 3 and 4, Sentry can register `SentryAppender` for you once the application context refreshes. This auto-configuration is opt-in:
+
+```properties
+sentry.logging.enabled=true
+```
+
+If Log4j 2 isn't the active logging backend, the appender isn't added.
+
+Minimum logging levels for `SentryAppender` can be configured in `application.properties` or `application.yml` file.
+
+```properties
+sentry.logging.minimum-event-level=info
+sentry.logging.minimum-breadcrumb-level=debug
+sentry.logging.minimum-level=debug
+```
+
+The default values are:
+
+- `info` or higher to include a log message as breadcrumb.
+- `info` or higher will send a log message to Sentry and will show up in the Logs section.
+- `error` or higher will send an event to Sentry and will show up in the Issues section.
+
+The appender is added to the root logger by default. To attach it to specific loggers instead, configure their names:
+
+```properties
+sentry.logging.loggers[0]=com.example.orders
+sentry.logging.loggers[1]=com.example.payments
+```
+
+Use non-overlapping logger names. Log4j 2 loggers are additive by default, so attaching the appender to both a logger and one of its ancestors can send the same log entry twice.
+
 ### XML Configuration
 
-[Follow the guide on configuring Log4j 2 with Spring Boot](https://docs.spring.io/spring-boot/docs/current/reference/html/howto.html#howto-configure-log4j-for-logging) and configure `SentryAppender` in the `log4j2.xml` file:
+Spring Boot 2 doesn't support `SentryAppender` auto-configuration, and errors logged before the Spring context refreshes aren't captured by it. In both cases, leave `sentry.logging.enabled` unset and configure `SentryAppender` in the `log4j2.xml` file:
 
 ```xml
 <?xml version="1.0" encoding="UTF-8"?>