Hi @fzyzcjy excellent question!
Here is an outline our release process along with key testing phases of each of our releases in this blog: How our remote team ships Mattermost like clockwork
The release process includes a mix of automated and manual testing carried out each month to ensure a high quality, stable release.
We are also working on a full QA test automation of the core features of the platform, including an end-to-end testing hackathon currently on-going with our community: E2E Test Automation Hackathon (May 3 - 31)
Finally, we also support an Extended Support Release (ESR), which is intended for organizations who value stability over having the newest features and improvements, or who have a long internal testing and certification process to undergo when upgrading.
Hopefully this is helpful! If you have any further questions, I’d be happy to help clarify!
Jason