Index: trunk/resources/data/validator/deprecated.mapcss
===================================================================
--- trunk/resources/data/validator/deprecated.mapcss	(revision 19467)
+++ trunk/resources/data/validator/deprecated.mapcss	(revision 19590)
@@ -2333,4 +2333,27 @@
 }
 
+/* #20421 */
+*[transformer=minor_distribution] {
+  throwWarning: tr("{0} is deprecated", "{1.tag}");
+  suggestAlternative: "transformer=distribution";
+  group: tr("deprecated tagging");
+  fixAdd: "transformer=distribution";
+}
+
+*[transformer=traction] {
+  throwWarning: tr("{0} is deprecated", "{0.tag}");
+  suggestAlternative: "transformer=main";
+  group: tr("deprecated tagging");
+  fixAdd: "transformer=main";
+}
+
+*[transformer=auto] {
+  throwWarning: tr("{0} is deprecated", "{0.tag}");
+  suggestAlternative: "transformer=* + windings:auto=yes";
+  group: tr("deprecated tagging");
+  fixRemove: "transformer";
+  fixAdd: "windings:auto=yes";
+}
+
 /* #20434 */
 *[building:roof:shape] {