Rated 5 out of 5 stars
Update 28-Jun-2012: I stand corrected.
• 2.1.0 works well with FF13 (FF14b appears to work as well...Will need to wait for a few more days to see the Days-Folder build up). Rating is now changed to 5 Stars.
• 2.1.0 only partially works (showing date on mouse over) with Aurora (FF15a) or Nightly (FF16a). There are no Days-Folder.
• 2.0.3 still works great with FF10 ESR.
Tried the updated version (2.04 and 2.10) on FF13+, the URLs are no longer separated by Days-Folder (i.e. Today, Yesterday, 2-Days Ago, 3-Days Ago, etc.).
On FF12. the update also messed up the history Days-Folder. Reinstalling the extension did not return it back to normal.
2.1.0 is only for Firefox 13 and later.
Please post your screenshots of history menu and last 7 days history in library: