diff --git a/CHANGES.md b/CHANGES.md
index e24cb224..1fb4bc50 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,30 @@
 # Changelog
 
+## 4.2.0
+
+Added:
+* Add `isruleset()` function (Hannah Okwelum) [T354895](https://phabricator.wikimedia.org/T354895)
+* Add source details to "Operation on an invalid type" error (Hannah Okwelum) [T344197](https://phabricator.wikimedia.org/T344197)
+* Add support for `method=relative` parameter in color functions (Hannah Okwelum) [T354895](https://phabricator.wikimedia.org/T354895)
+* Add support for comments in variables and function parameters (Hannah Okwelum) [T354895](https://phabricator.wikimedia.org/T354895)
+* Less_Parser: Add `functions` parser option API (Hannah Okwelum)
+
+Changed, to match Less.js 2.5.3:
+* Preserve original color keywords and shorthand hex (Hannah Okwelum) [T352866](https://phabricator.wikimedia.org/T352866)
+
+Fixed:
+* Fix PHP Warning when using a dynamic variable name like `@@name` (Hannah Okwelum) [T352830](https://phabricator.wikimedia.org/T352830)
+* Fix PHP Warning when `@extend` path contains non-quoted attribute (Gr8b) [T349433](https://phabricator.wikimedia.org/T349433)
+* Less_Parser: Faster `skipWhitespace` by using native `strspn` (Umherirrender)
+* Less_Parser: Fix Less_Tree_JavaScript references to consistently be in camel-case (Stefan Fröhlich)
+* Fix `!important` in nested mixins (Hannah Okwelum) [T353141](https://phabricator.wikimedia.org/T353141)
+* Fix crash when using recursive mixins (Timo Tijhof) [T352829](https://phabricator.wikimedia.org/T352829)
+* Fix disappearing selectors in certain nested blocks (Hannah Okwelum) [T352859](https://phabricator.wikimedia.org/T352859)
+* Fix Less_Exception_Compiler when passing unquoted value to `color()` (Hannah Okwelum) [T353289](https://phabricator.wikimedia.org/T353289)
+* Fix order of comments in `@font-face` blocks (Timo Tijhof) [T356706](https://phabricator.wikimedia.org/T356706)
+* Fix string comparison to ignore quote type (Timo Tijhof) [T357160](https://phabricator.wikimedia.org/T357160)
+* Fix string interpolation in selectors (Hannah Okwelum) [T353142](https://phabricator.wikimedia.org/T353142)
+
 ## 4.1.1
 
 * Less_Parser: Faster `MatchQuoted` by using native `strcspn`. (Thiemo Kreuz)
diff --git a/lib/Less/Version.php b/lib/Less/Version.php
index 4324805b..6b92f29b 100644
--- a/lib/Less/Version.php
+++ b/lib/Less/Version.php
@@ -6,11 +6,11 @@
 class Less_Version {
 
 	/* Current release version of less.php */
-	public const version = '4.1.0';
+	public const version = '4.2.0';
 
 	/* Upstream less.js version that this release should be compatible with */
 	public const less_version = '2.5.3';
 
 	/* Parser cache version */
-	public const cache_version = '253';
+	public const cache_version = '253-1';
 }