Index: trunk/resources/data/validator/deprecated.mapcss
===================================================================
--- trunk/resources/data/validator/deprecated.mapcss	(revision 18633)
+++ trunk/resources/data/validator/deprecated.mapcss	(revision 18642)
@@ -514,4 +514,17 @@
 }
 
+/* #22481 */
+*[building:level][!building:levels] {
+  throwWarning: tr("{0} is deprecated", "{1.key}");
+  suggestAlternative: "building:levels";
+  group: tr("deprecated tagging");
+  fixChangeKey: "building:level => building:levels";
+}
+*[building:level][building:levels] {
+  throwWarning: tr("{0} is deprecated", "{1.key}");
+  suggestAlternative: "building:levels";
+  group: tr("deprecated tagging");
+}
+
 /* #10691 */
 *[protected_class] {