diff --git a/migrations/env.py b/migrations/env.py
index 7d4d697..0c5f7bc 100644
--- a/migrations/env.py
+++ b/migrations/env.py
@@ -139,6 +139,20 @@ def run_migrations_online():
         pass
 
     with connectable.connect() as connection:
+        # Relax the session sql_mode for the migration run. Some historical
+        # migrations seed reference rows with raw INSERTs that omit NOT-NULL
+        # timestamp columns (the ORM supplies those via Python defaults at
+        # runtime, but a raw migration INSERT does not). MySQL 5.x's lax default
+        # accepted that; strict MySQL 8 rejects it with 1364 "Field 'createddate'
+        # doesn't have a default value". Dropping STRICT_TRANS_TABLES for the
+        # migration session only (the app's own connections keep their mode)
+        # makes the chain portable across MySQL versions.
+        try:
+            connection.exec_driver_sql(
+                "SET SESSION sql_mode = 'NO_ENGINE_SUBSTITUTION'")
+        except Exception:
+            pass  # non-MySQL backends (e.g. sqlite in tests)
+
         context.configure(
             connection=connection,
             target_metadata=get_metadata(),