diff --git a/lnschema_core/__init__.py b/lnschema_core/__init__.py
index b7e83a6b..cce980d5 100644
--- a/lnschema_core/__init__.py
+++ b/lnschema_core/__init__.py
@@ -43,7 +43,7 @@
 """
 # This is lnschema-module yvzi.
 _schema_id = "yvzi"
-_migration = "049d7dfc80a8"
+_migration = "1f29517759b7"
 __version__ = "0.7.2"  # denote a pre-release for 0.1.0 with 0.1a1
 
 from . import id, type  # noqa
diff --git a/lnschema_core/migrations/versions/2022-09-24-1f29517759b7-v0_7_3.py b/lnschema_core/migrations/versions/2022-09-24-1f29517759b7-v0_7_3.py
new file mode 100644
index 00000000..a15a0802
--- /dev/null
+++ b/lnschema_core/migrations/versions/2022-09-24-1f29517759b7-v0_7_3.py
@@ -0,0 +1,83 @@
+"""v0.7.3.
+
+Revision ID: 1f29517759b7
+Revises: 049d7dfc80a8
+Create Date: 2022-09-24 10:32:37.801549
+
+"""
+import sqlalchemy as sa  # noqa
+import sqlmodel  # noqa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = "1f29517759b7"
+down_revision = "049d7dfc80a8"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    with op.batch_alter_table("dobject", schema=None) as batch_op:
+        batch_op.alter_column(
+            "created_at",
+            existing_type=sa.DATETIME(),
+            nullable=False,
+            existing_server_default=sa.text("(CURRENT_TIMESTAMP)"),
+        )
+
+    with op.batch_alter_table("jupynb", schema=None) as batch_op:
+        batch_op.alter_column(
+            "created_at",
+            existing_type=sa.DATETIME(),
+            nullable=False,
+            existing_server_default=sa.text("(CURRENT_TIMESTAMP)"),
+        )
+
+    with op.batch_alter_table("pipeline", schema=None) as batch_op:
+        batch_op.alter_column(
+            "created_at",
+            existing_type=sa.DATETIME(),
+            nullable=False,
+            existing_server_default=sa.text("(CURRENT_TIMESTAMP)"),
+        )
+
+    with op.batch_alter_table("pipeline_run", schema=None) as batch_op:
+        batch_op.alter_column(
+            "created_at",
+            existing_type=sa.DATETIME(),
+            nullable=False,
+            existing_server_default=sa.text("(CURRENT_TIMESTAMP)"),
+        )
+
+    with op.batch_alter_table("storage", schema=None) as batch_op:
+        batch_op.alter_column(
+            "created_at",
+            existing_type=sa.DATETIME(),
+            nullable=False,
+            existing_server_default=sa.text("(CURRENT_TIMESTAMP)"),
+        )
+
+    with op.batch_alter_table("user", schema=None) as batch_op:
+        batch_op.alter_column(
+            "created_at",
+            existing_type=sa.DATETIME(),
+            nullable=False,
+            existing_server_default=sa.text("(CURRENT_TIMESTAMP)"),
+        )
+        batch_op.drop_constraint("user", type_="unique")
+        batch_op.drop_index("ix_user_email")
+        batch_op.create_index(batch_op.f("ix_user_email"), ["email"], unique=True)
+        batch_op.drop_index("ix_user_handle")
+        batch_op.create_index(batch_op.f("ix_user_handle"), ["handle"], unique=True)
+
+    with op.batch_alter_table("version_yvzi", schema=None) as batch_op:
+        batch_op.alter_column(
+            "created_at",
+            existing_type=sa.DATETIME(),
+            nullable=False,
+            existing_server_default=sa.text("(CURRENT_TIMESTAMP)"),
+        )
+
+
+def downgrade() -> None:
+    pass
diff --git a/tests/testdb.lndb b/tests/testdb.lndb
index cc60c3f5..610d847c 100644
Binary files a/tests/testdb.lndb and b/tests/testdb.lndb differ