diff --git a/ChangeLog.md b/ChangeLog.md
index 3c82a8ad..a94bea5a 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,103 @@
+# wolfCOSE Release 2.0.0 (September 2026)
+
+Release 2.0.0 builds on the first stable wolfCOSE release with a delegated
+(external) signing seam, expanded COSE_Key and CBOR helper APIs, exact
+encoded-size queries, a broad parsing and key-handling hardening pass, and
+initial experimental support for several additional COSE specifications. It
+remains a zero-allocation C implementation of CBOR (RFC 8949) and COSE
+(RFC 9052/9053) on top of wolfCrypt, with a path to FIPS 140-3 through
+wolfCrypt.
+
+This is a major release because `WOLFCOSE_KEY` gained fields since 1.0.0 (see
+Compatibility below). Applications must be recompiled against the 2.0.0
+headers; no source changes are needed for code that attaches keys through the
+`wc_CoseKey_Set*()` APIs and initializes with `wc_CoseKey_Init()`.
+
+## Vulnerabilities
+
+* No CVEs were assigned for this release.
+
+## New Feature Additions
+
+* Delegated (external) signing seam: `WOLFCOSE_ENABLE_EXT_SIGN` adds a signing
+  callback (`signCb` / `signCtx` on `WOLFCOSE_KEY`) so COSE_Sign1 and COSE_Sign
+  signatures can be produced by an external signer (HSM, secure element, remote
+  KMS) instead of a local wolfCrypt key.
+  ([#59](https://github.com/wolfSSL/wolfCOSE/pull/59))
+* `wc_CoseSign1_Sign_ex()` and `wc_CoseSign1_SignSize_ex()` add an untagged
+  COSE_Sign1 output option and an exact encoded-size query that reports the
+  size without signing.
+  ([#65](https://github.com/wolfSSL/wolfCOSE/pull/65))
+* Expanded COSE_Key API: `wc_CoseKey_Encode_ex()` with a
+  `WOLFCOSE_KEY_PUBLIC_ONLY` flag that never serialises private material, exact
+  `wc_CoseKey_EncodeSize()` / `wc_CoseKey_EncodeSize_ex()` size queries,
+  `wc_CoseKey_EncodeEccRaw()` for raw affine coordinates, and
+  `wc_CoseKey_PeekInfo()` to read key metadata before decoding.
+  ([#66](https://github.com/wolfSSL/wolfCOSE/pull/66))
+* New CBOR helpers for parsing maps wolfCOSE does not itself define:
+  `wc_CBOR_EncoderInit` / `wc_CBOR_DecoderInit`, `wc_CBOR_DecodeLabel` for
+  int-or-text map labels, and `wc_CBOR_SkipItem` to capture a skipped item's
+  raw bytes.
+  ([#66](https://github.com/wolfSSL/wolfCOSE/pull/66))
+* Experimental-feature acknowledgment gate: draft, pre-RFC COSE features are
+  held behind `WOLFCOSE_EXPERIMENTAL` plus a per-feature `WOLFCOSE_ENABLE_<X>`;
+  selecting a draft feature without the master acknowledgment is a hard compile
+  error.
+  ([#68](https://github.com/wolfSSL/wolfCOSE/pull/68))
+
+### Experimental additions (opt-in, off by default)
+
+New, opt-in implementations gated behind their own `WOLFCOSE_ENABLE_<X>` build
+flags while they mature; see `docs/Macros.md`.
+
+* RFC 8778 HSS/LMS signature and COSE_Key support.
+  ([#72](https://github.com/wolfSSL/wolfCOSE/pull/72))
+* RFC 9338 countersignature support.
+  ([#74](https://github.com/wolfSSL/wolfCOSE/pull/74))
+* RFC 9783 PSA/EAT support.
+  ([#75](https://github.com/wolfSSL/wolfCOSE/pull/75))
+* COSE-HPKE support. This tracks an IETF Internet-Draft that is not yet a
+  finalized RFC, so it additionally requires the `WOLFCOSE_EXPERIMENTAL`
+  acknowledgment and its wire format and API may still change.
+  ([#70](https://github.com/wolfSSL/wolfCOSE/pull/70))
+
+## Fixes
+
+* Hardened COSE_Key decoding so an attached key is only ever imported as its
+  actual type: a decode whose key type does not match the attached key object
+  is now rejected before any import runs. Thanks to Omoikane Labs for reporting.
+  ([#64](https://github.com/wolfSSL/wolfCOSE/pull/64))
+* Broad hardening pass across COSE parsing, key handling, and cryptographic
+  operations, adding input validation and robustness throughout the decode and
+  key paths.
+  ([#67](https://github.com/wolfSSL/wolfCOSE/pull/67))
+
+## Improvements/Optimizations
+
+* Split the monolithic `wolfcose.c` into per-area source modules for
+  maintainability and finer-grained builds.
+  ([#73](https://github.com/wolfSSL/wolfCOSE/pull/73))
+* Build discovery now uses `pkg-config` for system-installed wolfSSL.
+  ([#69](https://github.com/wolfSSL/wolfCOSE/pull/69))
+* Expanded COSE interoperability coverage against external COSE
+  implementations.
+  ([#71](https://github.com/wolfSSL/wolfCOSE/pull/71))
+* STM32Cube pack support: I-CUBE-wolfCOSE pack files, an on-device test, and
+  documentation.
+  ([#61](https://github.com/wolfSSL/wolfCOSE/pull/61))
+* Stabilized the nightly cppcheck static-analysis job on `test_cose.c`.
+  ([#62](https://github.com/wolfSSL/wolfCOSE/pull/62))
+
+## Compatibility / Migration
+
+* ABI: `WOLFCOSE_KEY` gained tail fields since 1.0.0 (the delegated-signing
+  callback and context, and internal key-type tracking), so
+  `sizeof(WOLFCOSE_KEY)` differs from 1.0.0. Recompile applications against the
+  2.0.0 headers. Code that attaches keys through `wc_CoseKey_Set*()` and
+  initializes with `wc_CoseKey_Init()` needs no source changes.
+* `LIBWOLFCOSE_VERSION_STRING` is now `"2.0.0"`
+  (`LIBWOLFCOSE_VERSION_HEX 0x02000000`).
+
 # wolfCOSE Release 1.0.0 (June 25, 2026)
 
 Release 1.0.0 is the first stable release of wolfCOSE, a complete,
diff --git a/README.md b/README.md
index 1675a525..49d07325 100644
--- a/README.md
+++ b/README.md
@@ -236,9 +236,9 @@ Full documentation is available in the [Wiki](https://github.com/wolfSSL/wolfCOS
 
 ## Release Notes
 
-The current release is **1.0.0**, the first stable release: the complete RFC 9052 COSE message set (all six message types, single- and multi-actor), 40 algorithms, and standardized post-quantum ML-DSA (RFC 9964), all with zero dynamic allocation. See [ChangeLog.md](ChangeLog.md) for the full release notes.
+The current release is **2.0.0**. It builds on the first stable release with a delegated (external) signing seam, expanded COSE_Key and CBOR helper APIs, exact encoded-size queries, a broad parsing and key-handling hardening pass, and initial experimental support for additional COSE specifications, all with zero dynamic allocation. See [ChangeLog.md](ChangeLog.md) for the full release notes.
 
-wolfCOSE 1.0.0 has been developed according to wolfSSL's development and QA process (see https://www.wolfssl.com/about/wolfssl-software-development-process-quality-assurance) and successfully passed the quality criteria.
+wolfCOSE 2.0.0 has been developed according to wolfSSL's development and QA process (see https://www.wolfssl.com/about/wolfssl-software-development-process-quality-assurance) and successfully passed the quality criteria.
 
 ## License
 
diff --git a/docs/Release-Notes.md b/docs/Release-Notes.md
index 2ce136e0..925945ba 100644
--- a/docs/Release-Notes.md
+++ b/docs/Release-Notes.md
@@ -1,5 +1,94 @@
 # Release Notes
 
+## wolfCOSE 2.0.0 (September 2026)
+
+Release 2.0.0 builds on the first stable wolfCOSE release with a delegated
+(external) signing seam, expanded COSE_Key and CBOR helper APIs, exact
+encoded-size queries, a broad parsing and key-handling hardening pass, and
+initial experimental support for several additional COSE specifications. It
+remains a zero-allocation C implementation of CBOR (RFC 8949) and COSE
+(RFC 9052/9053) on top of wolfCrypt.
+
+This is a major release because `WOLFCOSE_KEY` gained fields since 1.0.0 (see
+Compatibility below). Applications must be recompiled against the 2.0.0
+headers; no source changes are needed for code that attaches keys through the
+`wc_CoseKey_Set*()` APIs and initializes with `wc_CoseKey_Init()`.
+
+### Vulnerabilities
+
+- No CVEs were assigned for this release.
+
+### New Feature Additions
+
+- Delegated (external) signing seam: `WOLFCOSE_ENABLE_EXT_SIGN` adds a signing
+  callback (`signCb` / `signCtx` on `WOLFCOSE_KEY`) so COSE_Sign1 and COSE_Sign
+  signatures can be produced by an external signer (HSM, secure element, remote
+  KMS) instead of a local wolfCrypt key.
+  ([#59](https://github.com/wolfSSL/wolfCOSE/pull/59))
+- `wc_CoseSign1_Sign_ex()` and `wc_CoseSign1_SignSize_ex()` add an untagged
+  COSE_Sign1 output option and an exact encoded-size query.
+  ([#65](https://github.com/wolfSSL/wolfCOSE/pull/65))
+- Expanded COSE_Key API: `wc_CoseKey_Encode_ex()` with a
+  `WOLFCOSE_KEY_PUBLIC_ONLY` flag, exact `wc_CoseKey_EncodeSize()` /
+  `wc_CoseKey_EncodeSize_ex()` queries, `wc_CoseKey_EncodeEccRaw()` for raw
+  affine coordinates, and `wc_CoseKey_PeekInfo()` to read key metadata before
+  decoding. ([#66](https://github.com/wolfSSL/wolfCOSE/pull/66))
+- New CBOR helpers: `wc_CBOR_EncoderInit` / `wc_CBOR_DecoderInit`,
+  `wc_CBOR_DecodeLabel` for int-or-text map labels, and `wc_CBOR_SkipItem` to
+  capture a skipped item's raw bytes.
+  ([#66](https://github.com/wolfSSL/wolfCOSE/pull/66))
+- Experimental-feature acknowledgment gate: draft, pre-RFC features are held
+  behind `WOLFCOSE_EXPERIMENTAL` plus a per-feature `WOLFCOSE_ENABLE_<X>`;
+  selecting a draft feature without the acknowledgment is a hard compile error.
+  ([#68](https://github.com/wolfSSL/wolfCOSE/pull/68))
+
+#### Experimental additions (opt-in, off by default)
+
+New, opt-in implementations gated behind their own `WOLFCOSE_ENABLE_<X>` build
+flags while they mature; see [[Macros]].
+
+- RFC 8778 HSS/LMS signature and COSE_Key support.
+  ([#72](https://github.com/wolfSSL/wolfCOSE/pull/72))
+- RFC 9338 countersignature support.
+  ([#74](https://github.com/wolfSSL/wolfCOSE/pull/74))
+- RFC 9783 PSA/EAT support. ([#75](https://github.com/wolfSSL/wolfCOSE/pull/75))
+- COSE-HPKE support. This tracks an IETF Internet-Draft that is not yet a
+  finalized RFC, so it additionally requires the `WOLFCOSE_EXPERIMENTAL`
+  acknowledgment and its wire format and API may still change.
+  ([#70](https://github.com/wolfSSL/wolfCOSE/pull/70))
+
+### Fixes
+
+- Hardened COSE_Key decoding so an attached key is only ever imported as its
+  actual type; a decode whose key type does not match the attached key object
+  is now rejected before any import runs. Thanks to Omoikane Labs for reporting.
+  ([#64](https://github.com/wolfSSL/wolfCOSE/pull/64))
+- Broad hardening pass across COSE parsing, key handling, and cryptographic
+  operations. ([#67](https://github.com/wolfSSL/wolfCOSE/pull/67))
+
+### Improvements/Optimizations
+
+- Split the monolithic `wolfcose.c` into per-area source modules.
+  ([#73](https://github.com/wolfSSL/wolfCOSE/pull/73))
+- Build discovery now uses `pkg-config` for system-installed wolfSSL.
+  ([#69](https://github.com/wolfSSL/wolfCOSE/pull/69))
+- Expanded COSE interoperability coverage against external implementations.
+  ([#71](https://github.com/wolfSSL/wolfCOSE/pull/71))
+- STM32Cube pack support: I-CUBE-wolfCOSE pack files, an on-device test, and
+  documentation. ([#61](https://github.com/wolfSSL/wolfCOSE/pull/61))
+- Stabilized the nightly cppcheck static-analysis job on `test_cose.c`.
+  ([#62](https://github.com/wolfSSL/wolfCOSE/pull/62))
+
+### Compatibility / Migration
+
+- ABI: `WOLFCOSE_KEY` gained tail fields since 1.0.0 (the delegated-signing
+  callback and context, and internal key-type tracking), so
+  `sizeof(WOLFCOSE_KEY)` differs from 1.0.0. Recompile applications against the
+  2.0.0 headers. Code that attaches keys through `wc_CoseKey_Set*()` and
+  initializes with `wc_CoseKey_Init()` needs no source changes.
+- `LIBWOLFCOSE_VERSION_STRING` is now `"2.0.0"`
+  (`LIBWOLFCOSE_VERSION_HEX 0x02000000`).
+
 ## wolfCOSE 1.0.0 (June 25, 2026)
 
 Release 1.0.0 is the first stable release of wolfCOSE, a complete,
diff --git a/include/wolfcose/version.h b/include/wolfcose/version.h
index 6dfd85f6..c8e8bc93 100644
--- a/include/wolfcose/version.h
+++ b/include/wolfcose/version.h
@@ -25,8 +25,8 @@
 extern "C" {
 #endif
 
-#define LIBWOLFCOSE_VERSION_STRING "1.0.0"
-#define LIBWOLFCOSE_VERSION_HEX 0x01000000
+#define LIBWOLFCOSE_VERSION_STRING "2.0.0"
+#define LIBWOLFCOSE_VERSION_HEX 0x02000000
 
 #ifdef __cplusplus
 }