diff --git a/public/css/icinga/compat.less b/public/css/icinga/compat.less
index 0195fb75e..9c1be1d35 100644
--- a/public/css/icinga/compat.less
+++ b/public/css/icinga/compat.less
@@ -32,3 +32,9 @@ table.action {
 table.avp {
   .name-value-table()
 }
+
+.code() {
+  // Some 3rd party modules (e.g. vsphere) use this mixin (though we never had it)
+  // With lessphp version 0.5.0 using undefined mixins now throws exceptions
+  // Since we can't rely that users upgrade those modules first, we provide the mixin for compatibility here
+}