It’s still got the beta-1 in the version but apparently it’s not going to be doing much more, if anything. The download link in the sidebar will now get you just the changed files from 1.5.2. There are 13 files in the download and ordinarily you wouldn’t have changed them. Change the old for the new ones. (backup first of course).
Note: As of now, 1.5.x is not under development. You are still encouraged to upgrade to version 2.x but for now only 1.5.3 and 2.0.2 can be considered secure – so if you haven’t got one of those, upgrade!