There are a lot of different Version Control Systems out there. Over the years, some of them have become more popular than others.
While the IntelliJ platform provides Integration with various VCSs out of the box, the usage for some of these have steadily declined, to the point that a few of them have very little support demand whatsoever. As such, we’ve decided to reduce the number of VCSs supported out-of-the-box and focus on improving the most popular ones.
What does this mean?
Visual SourceSafe has reached its end-of-life, and ClearCase is approaching it next year. Given this, along with the low demand and popularity for these integrations, we no longer plan to continue development on these plugins, and will be closing their support as of 2017.3 release.
A separate announcement will follow when it happens.
Note that plugins will stay available in the repository, and we will maintain compatibility with successive versions of the IntelliJ platform, making sure no critical regressions are introduced.