5.2 came out a little over a week ago and 5.2.1 fixes a few small bugs found in that release. Download it now. Among the useful changes, PNG images will upload to blog servers and look better. Configuring new Picasa settings should work better now. Spell checking should work better in Full Screen. There are a few other small changes, which you can check out in the Version History item in the Help menu.
If you have any issues in this release, please email me as soon as possible as this release will hopefully have a much shorter cycle than 5.2.