diff --git a/CHANGELOG.md b/CHANGELOG.md
index 293251cc..d8853c74 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,12 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+## [0.6.4] - 2021-08-03
+
+### Changed
+- Update contour to 1.18.0 (#68)
+  - Add support for the newly added HTTPProxy.Spec.IngressClassName
+
 ## [0.6.3] - 2021-07-27
 
 ### Changed
@@ -166,7 +172,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
     - for [ExternalDNS][] v0.5.14
     - for [cert-manager][] v0.8.0
 
-[Unreleased]: https://github.com/cybozu-go/contour-plus/compare/v0.6.3...HEAD
+[Unreleased]: https://github.com/cybozu-go/contour-plus/compare/v0.6.4...HEAD
+[0.6.4]: https://github.com/cybozu-go/contour-plus/compare/v0.6.3...v0.6.4
 [0.6.3]: https://github.com/cybozu-go/contour-plus/compare/v0.6.2...v0.6.3
 [0.6.2]: https://github.com/cybozu-go/contour-plus/compare/v0.6.1...v0.6.2
 [0.6.1]: https://github.com/cybozu-go/contour-plus/compare/v0.6.0...v0.6.1
diff --git a/README.md b/README.md
index 5393c4ae..f6f43b09 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ Supported environments
 - Kubernetes
   - 1.21
 - Contour
-  - 1.17
+  - 1.18
 - ExternalDNS
   - 0.7
 - cert-manager
diff --git a/RELEASE.md b/RELEASE.md
index f5e132af..e1cc1405 100644
--- a/RELEASE.md
+++ b/RELEASE.md
@@ -37,7 +37,7 @@ Bump version
 2. Make a branch to release
 
     ```console
-    $ git neco dev "$VERSION"`
+    $ git neco dev "$VERSION"
     ```
 
 4. Edit `CHANGELOG.md` for the new version ([example][]).