This blog is a follow-up to the information we shared in June and July about our ongoing security hardening. It covers:
- Updating default message library on Endpoint v1
- Relayer deprecation for LayerZero v1 on December 15, 2026
Updating Default Message Library on Endpoint v1
We successfully completed the scheduled update to the Endpoint v1 default message library from ULNv2 to ULNv301 on August 4th. All applications using default message libraries on active pathways are now secured by a minimum 3-of-3 configuration.
This update only affects applications using Endpoint v1 with the default message library. For applications that were not using custom adapter parameters, please setUseCustomAdapterParams as True and call setMinDstGas to set the minimum gas as documented in the integration checklist. Passing no argument (empty bytes) as adapterParams reverts with the error InvalidWorkerOptions in ULNv301. Please ensure the messages are sent with explicit adapterParams.
As a best practice reminder, we recommend that all teams configure their security stack beyond defaults.
LayerZero Labs Relayer Deprecation Scheduled for December 15, 2026
The LayerZero Labs Relayer that services LayerZero v1 (ULNv2) will be deprecated on December 15, 2026.
Teams currently pinned to the ULNv2 in Endpoint v1 will need to change their library to ULNv301 before this date. Failing to update to ULNv301 before the LayerZero Labs Relayer deprecation will leave messages unable to be executed.
Teams that want to stay on ULNv2 can run their own relayer.
For any teams with questions about this update, please reach out to your LayerZero point of contact.