diff --git a/.eslintignore b/.eslintignore
index 5e12643cf815a..b512e29ef62e8 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -20,7 +20,6 @@ lib/mlbackend/php/phpml/
 lib/adodb/
 lib/bennu/
 lib/evalmath/
-lib/lessphp/
 lib/phpexcel/
 lib/google/
 lib/htmlpurifier/
diff --git a/.stylelintignore b/.stylelintignore
index a22b9cce9fc24..da80cf568f41e 100644
--- a/.stylelintignore
+++ b/.stylelintignore
@@ -21,7 +21,6 @@ lib/mlbackend/php/phpml/
 lib/adodb/
 lib/bennu/
 lib/evalmath/
-lib/lessphp/
 lib/phpexcel/
 lib/google/
 lib/htmlpurifier/
diff --git a/lib/thirdpartylibs.xml b/lib/thirdpartylibs.xml
index 505ae73694fae..8f8bf1f8cde1f 100644
--- a/lib/thirdpartylibs.xml
+++ b/lib/thirdpartylibs.xml
@@ -21,13 +21,6 @@
     <version></version>
     <licenseversion></licenseversion>
   </library>
-  <library>
-    <location>lessphp</location>
-    <name>less.php</name>
-    <license>Apache</license>
-    <version>1.7.0.10</version>
-    <licenseversion>2.0</licenseversion>
-  </library>
   <library>
     <location>phpexcel</location>
     <name>PHPExcel</name>
diff --git a/theme/upgrade.txt b/theme/upgrade.txt
index 924f4ec1e26c0..3f281b66f0402 100644
--- a/theme/upgrade.txt
+++ b/theme/upgrade.txt
@@ -1,6 +1,11 @@
 This files describes API changes in /theme/* themes,
 information provided here is intended especially for theme designer.
 
+=== 3.8 ===
+
+* The PHP Less compilier has now been removed from the core library.
+  Please consider migrating your theme to use SCSS.
+
 === 3.7 ===
 * The core/form_autocompelte_input template now has a `data-tags` attribute.
 * Boost theme renderer overrides have now been migrated to core.