diff --git a/src/Model/Migration.hs b/src/Model/Migration.hs
index f0f190a79..e7ad3c9af 100644
--- a/src/Model/Migration.hs
+++ b/src/Model/Migration.hs
@@ -526,6 +526,9 @@ customMigrations = Map.fromListWith (>>)
   , ( AppliedMigrationKey [migrationVersion|21.0.0|] [version|22.0.0|]
     , whenM (tableExists "exam") $
         [executeQQ|
+          ALTER TABLE "exam" DROP COLUMN IF EXISTS "grading_key";
+          ALTER TABLE "exam" ADD COLUMN IF NOT EXISTS "grading_rule" jsonb;
+
           ALTER TABLE "exam" ALTER COLUMN "grading_rule" DROP NOT NULL;
           ALTER TABLE "exam" ALTER COLUMN "bonus_rule" DROP NOT NULL;
           ALTER TABLE "exam" ALTER COLUMN "occurrence_rule" DROP NOT NULL;