Performance was a focus area of Mattermost 3.5 and in updating the system to smoothly scale from small teams to very large organizations on a single machine meant making some breaking changes to the API.
Specifically, routes that could potentially reduce performance were replaced with solutions supporting paging and greater scale.
If you’re using the Mattermost drivers, those have been updated to minimize issues with API changes:
Any questions or comments, please let us know?