diff --git a/vlorentz/migrate_extra_headers.py b/vlorentz/migrate_extra_headers.py
new file mode 100644
index 0000000..d5ede96
--- /dev/null
+++ b/vlorentz/migrate_extra_headers.py
@@ -0,0 +1,63 @@
+#!/usr/bin/env python3
+
+# Copyright (C) 2021  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+import functools
+
+import psycopg2
+import psycopg2.extras
+
+from swh.journal.client import get_journal_client
+
+
+def process_journal_objects(messages, *, conn):
+    assert set(messages) == {"revision"}, set(messages)
+    revisions = messages["revision"]
+
+    rows = []
+    for revision in revisions:
+        if revision.get("extra_headers"):
+            rows.append((revision["id"], revision["extra_headers"]))
+
+    cur = conn.cursor()
+    psycopg2.extras.execute_values(
+        cur,
+        """
+        UPDATE revision
+        SET extra_headers = data.extra_headers
+        FROM (VALUES %s) AS data (id, extra_headers)
+        WHERE
+            revision.id=data.id
+            AND (
+                -- Don't unnecessarily update rows that already have their
+                -- 'extra_headers' cell populated
+                revision.extra_headers = ARRAY[]::bytea[]
+                OR revision.extra_headers IS NULL
+            )
+        """,
+        rows,
+    )
+
+    print(f"processed {len(rows)} revisions")
+
+
+def main():
+    client = get_journal_client(
+        cls="kafka",
+        prefix="swh.journal.objects",
+        object_types=["revision"],
+        brokers=[f"kafka{i+1}.internal.softwareheritage.org:9092" for i in range(4)],
+        group_id="vlorentz-T2564-migrate-extra-headers",
+    )
+    conn = psycopg2.connect("service=swh")
+
+    worker_fn = functools.partial(process_journal_objects, conn=conn)
+
+    client.process(worker_fn)
+
+
+if __name__ == "__main__":
+    main()