diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index f59f62aa..e2169eb9 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,5 +1,5 @@
 {
     "tket2-py": "0.8.1",
-    "tket2-eccs": "0.3.0",
+    "tket2-eccs": "0.4.0",
     "tket2-exts": "0.7.0"
 }
diff --git a/tket2-eccs/CHANGELOG.md b/tket2-eccs/CHANGELOG.md
index b395ae7b..aa8c717c 100644
--- a/tket2-eccs/CHANGELOG.md
+++ b/tket2-eccs/CHANGELOG.md
@@ -1,5 +1,16 @@
 # Changelog
 
+## [0.4.0](https://github.com/CQCL/tket2/compare/tket2-eccs-v0.3.0...tket2-eccs-v0.4.0) (2025-05-16)
+
+
+### ⚠ BREAKING CHANGES
+
+* bump to hugr 0.20
+
+### Miscellaneous Chores
+
+* Bump to hugr-0.20 ([#862](https://github.com/CQCL/tket2/issues/862)) ([652a7d0](https://github.com/CQCL/tket2/commit/652a7d0b039bca62407f16f7548204e97f92ef5a))
+
 ## [0.3.0](https://github.com/CQCL/tket2/compare/tket2-eccs-v0.2.0...tket2-eccs-v0.3.0) (2024-12-16)
 
 
diff --git a/tket2-eccs/pyproject.toml b/tket2-eccs/pyproject.toml
index 5bad0f3e..b8c2d70c 100644
--- a/tket2-eccs/pyproject.toml
+++ b/tket2-eccs/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "tket2_eccs"
-version = "0.3.0"
+version = "0.4.0"
 requires-python = ">=3.10"
 description = "Precompiled rewrite sets for the tket 2 compiler"
 license = { file = "LICENCE" }
diff --git a/tket2-eccs/src/tket2_eccs/__init__.py b/tket2-eccs/src/tket2_eccs/__init__.py
index fa5488c9..f3d94f51 100644
--- a/tket2-eccs/src/tket2_eccs/__init__.py
+++ b/tket2-eccs/src/tket2_eccs/__init__.py
@@ -5,7 +5,7 @@
 
 # This is updated by our release-please workflow, triggered by this
 # annotation: x-release-please-version
-__version__ = "0.3.0"
+__version__ = "0.4.0"
 
 from importlib import resources
 from pathlib import Path