diff --git a/CHANGES.md b/CHANGES.md
index 3f39731b..641133d3 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,10 @@
 # Changelog
 
+## v5.1.1
+
+Fixed:
+* Fix compiling of PHP-injected variables with false, null or empty string (Hannah Okwelum)
+
 ## v5.1.0
 
 Added:
diff --git a/lib/Less/Version.php b/lib/Less/Version.php
index 60f7d05e..5339003a 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 = '5.1.0';
+	public const version = '5.1.1';
 
 	/* Upstream less.js version that this release should be compatible with */
 	public const less_version = '3.13.1';
 
 	/* Parser cache version */
-	public const cache_version = '3131-2';
+	public const cache_version = '3131-3';
 }