diff --git a/migrations/000140_drop_module_version_states_index_timestamp_not_null.down.sql b/migrations/000140_drop_module_version_states_index_timestamp_not_null.down.sql
new file mode 100644
index 0000000..20f52c3
--- /dev/null
+++ b/migrations/000140_drop_module_version_states_index_timestamp_not_null.down.sql
@@ -0,0 +1,9 @@
+-- Copyright 2021 The Go Authors. All rights reserved.
+-- Use of this source code is governed by a BSD-style
+-- license that can be found in the LICENSE file.
+
+BEGIN;
+
+ALTER TABLE module_version_states ALTER COLUMN index_timestamp SET NOT NULL;
+
+END;
diff --git a/migrations/000140_drop_module_version_states_index_timestamp_not_null.up.sql b/migrations/000140_drop_module_version_states_index_timestamp_not_null.up.sql
new file mode 100644
index 0000000..54f33a5
--- /dev/null
+++ b/migrations/000140_drop_module_version_states_index_timestamp_not_null.up.sql
@@ -0,0 +1,9 @@
+-- Copyright 2021 The Go Authors. All rights reserved.
+-- Use of this source code is governed by a BSD-style
+-- license that can be found in the LICENSE file.
+
+BEGIN;
+
+ALTER TABLE module_version_states ALTER COLUMN index_timestamp DROP NOT NULL;
+
+END;