--- a/hgext3rd/evolve/compat.py	Thu Oct 10 08:22:41 2019 +0700
+++ b/hgext3rd/evolve/compat.py	Sun Oct 06 02:30:12 2019 -0400
@@ -17,6 +17,7 @@
     obsolete,
     obsutil,
     pycompat,
+    registrar,
     repair,
     scmutil,
     util,
@@ -515,3 +516,12 @@
                      if meta.get(b'operation'))
 
     return sorted(operations)
+
+# help category compatibility
+# hg <= 4.7 (c303d65d2e34)
+def helpcategorykwargs(categoryname):
+    """Backwards-compatible specification of the helpategory argument."""
+    category = getattr(registrar.command, categoryname, None)
+    if not category:
+        return {}
+    return {'helpcategory': category}