1. Launch a tip-of-tree build of Brackets and make note of what's in the Recent Projects dropdown
2. Quit that version, and launch an earlier sprint build (I used Sprint 20)
3. Note that Recent Projects dropdown is blank. (This seems like an expected, though unfortunate, side effect of the preferences id migration).
4. Open some project other than the default Getting Started
5. Quit the older version, and re-launch the latest build

Result: Recent Projects dropdown contains the project you opened in step 4, the default Getting Started, and nothing else

Expected: Preferences from latest version are unharmed

This seems like a bit of an edge case, since it's unlikely to be running old builds after upgrading (except perhaps for Edge Code, but that uses a separate prefs store). However, it's still a little worrisome... might be worth pondering for a min before this sprint closes down.