Many issues have been fixed since that version, including issues related to changes in site software and hand histories, so you should really update.
The update shouldn't cause any problems, but I would always recommend making a
Backup of your database before updating, as you would do for any important document. If you don't still have all of your original hand history files (in the PokerTracker 3\Processed folder by default) then this may be a good time to do an
export too
Then just close PT3 and all your poker sites before running the installer, which you can download from the
Download page. I would recommend v3.11.6 Beta, which is lower down the page.