A feature which will allow a user to see the version of Powder that a save was uploaded or last updated in, either while viewing its description in the browser or client view or both. The main reason for doing such a thing is that there is always a chance of an update feature to break an older simulation, but a user who wishes to see an old simulation working as it should again can revert to the older version which it was intended to run on.
The "feature" already exists. If you hover your cursor over a save, you'll see a calender 7 icon on the bottom left. Click that to see past versions of saves. But if you use mobile, you'd have to press and hold a save to make that icon appear, and then press it.