Update Mattermost to 4.2.1 for GitLab 10.1.1
We've backported security issues fixed in the 4.3 release to 4.2.1 (4.2 shipped with GitLab 10.0 and 10.1) and 4.1.2 (4.1 shipped with GitLab 9.5).
Edited by Eric Sethna
We've backported security issues fixed in the 4.3 release to 4.2.1 (4.2 shipped with GitLab 10.0 and 10.1) and 4.1.2 (4.1 shipped with GitLab 9.5).