diff --git a/migrations/0012_sync_contract_hardening.down.sql b/migrations/0012_sync_contract_hardening.down.sql
new file mode 100644
index 0000000..37e4c21
--- /dev/null
+++ b/migrations/0012_sync_contract_hardening.down.sql
@@ -0,0 +1,16 @@
+ALTER TABLE staff_sync_command_inbox
+  DROP CONSTRAINT IF EXISTS staff_sync_command_inbox_correlation_id_check,
+  DROP CONSTRAINT IF EXISTS staff_sync_command_inbox_causation_id_check;
+
+ALTER TABLE staff_sync_command_inbox
+  ALTER COLUMN correlation_id TYPE VARCHAR(36),
+  ALTER COLUMN causation_id TYPE VARCHAR(36);
+
+ALTER TABLE staff_sync_devices
+  DROP CONSTRAINT IF EXISTS staff_sync_devices_tenant_id_org_unit_id_fkey;
+
+ALTER TABLE staff_sync_devices
+  ADD CONSTRAINT staff_sync_devices_tenant_id_org_unit_id_fkey
+  FOREIGN KEY (tenant_id, org_unit_id)
+  REFERENCES staff_org_units (tenant_id, id)
+  ON DELETE SET NULL;
diff --git a/migrations/0012_sync_contract_hardening.up.sql b/migrations/0012_sync_contract_hardening.up.sql
new file mode 100644
index 0000000..36abfaa
--- /dev/null
+++ b/migrations/0012_sync_contract_hardening.up.sql
@@ -0,0 +1,18 @@
+ALTER TABLE staff_sync_devices
+  DROP CONSTRAINT IF EXISTS staff_sync_devices_tenant_id_org_unit_id_fkey;
+
+ALTER TABLE staff_sync_devices
+  ADD CONSTRAINT staff_sync_devices_tenant_id_org_unit_id_fkey
+  FOREIGN KEY (tenant_id, org_unit_id)
+  REFERENCES staff_org_units (tenant_id, id)
+  ON DELETE RESTRICT;
+
+ALTER TABLE staff_sync_command_inbox
+  ALTER COLUMN correlation_id TYPE VARCHAR(26),
+  ALTER COLUMN causation_id TYPE VARCHAR(26);
+
+ALTER TABLE staff_sync_command_inbox
+  ADD CONSTRAINT staff_sync_command_inbox_correlation_id_check
+    CHECK (correlation_id ~ '^[0-9A-HJKMNP-TV-Z]{26}$'),
+  ADD CONSTRAINT staff_sync_command_inbox_causation_id_check
+    CHECK (causation_id IS NULL OR causation_id ~ '^[0-9A-HJKMNP-TV-Z]{26}$');