diff --git a/.version b/.version
index 2b2a18d..4add8a3 100644
--- a/.version
+++ b/.version
@@ -1 +1 @@
-0.4.20
+0.4.21
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 38c362b..c91f5a1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,17 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+## [0.4.21]
+
+### Added
+
+- Add rule `duplicate_id`, which detect xml element duplicate id [#126](https://github.com/IBDecodable/IBLinter/pull/126)
+- Add rule `reuse_identifier` which checks that ReuseIdentifier same as class name. [#137](https://github.com/IBDecodable/IBLinter/pull/137)
+
+### Fixed
+
+- Do not detect violations for system images for `image_resources` rule. [#131](https://github.com/IBDecodable/IBLinter/pull/131)
+
 ## [0.4.20]
 
 ### Fixed
@@ -77,7 +88,8 @@ Fix bug where IBLinter ignores to validate UICollectionViewCell. [#97](https://g
 - First version
 
 
-[Unreleased]: https://github.com/IBDecodable/IBLinter/compare/0.4.20...HEAD
+[Unreleased]: https://github.com/IBDecodable/IBLinter/compare/0.4.21...HEAD
+[0.4.21]: https://github.com/IBDecodable/IBLinter/compare/0.4.20...0.4.21
 [0.4.20]: https://github.com/IBDecodable/IBLinter/compare/0.4.19...0.4.20
 [0.4.19]: https://github.com/IBDecodable/IBLinter/compare/0.4.18...0.4.19
 [0.4.18]: https://github.com/IBDecodable/IBLinter/compare/0.4.17...0.4.18
diff --git a/Makefile b/Makefile
index 6da3cb0..17e174d 100644
--- a/Makefile
+++ b/Makefile
@@ -27,7 +27,7 @@ current_version:
 bump_version:
 		$(eval NEW_VERSION := $(filter-out $@,$(MAKECMDGOALS)))
 		@echo $(NEW_VERSION) > .version
-		@sed 's/__VERSION__/$(NEW_VERSION)/g' script/Version.swift.template > Sources/IBLinterFrontend/Version.swift
+		@sed 's/__VERSION__/$(NEW_VERSION)/g' script/Version.swift.template > Sources/IBLinterKit/Version.swift
 		git commit -am"Bump version to $(NEW_VERSION)"
 
 publish:
diff --git a/Sources/IBLinterKit/Version.swift b/Sources/IBLinterKit/Version.swift
index 1a1c106..51f2cf7 100644
--- a/Sources/IBLinterKit/Version.swift
+++ b/Sources/IBLinterKit/Version.swift
@@ -1,5 +1,5 @@
 public struct Version {
     public let value: String
 
-    public static let current = Version(value: "0.4.19")
+    public static let current = Version(value: "0.4.21")
 }