diff -r 1b0cb3c6c95e -r ab956b780d4e migration.py
--- a/migration.py	Wed Jul 30 22:26:18 2014 +0200
+++ b/migration.py	Mon Dec 01 11:13:10 2014 +0100
@@ -525,7 +525,7 @@
                 self.errors.append( ('add', cube, version, source) )
             elif versions:
                 lower_strict = version_strictly_lower(self.cubes[cube], version)
-                if oper in ('>=','='):
+                if oper in ('>=','=','=='):
                     if lower_strict:
                         self.errors.append( ('update', cube, version, source) )
                 elif oper is None: