For all who are using to a 5.1.x version. This is mostly a bug fix release and it is up to you if you want to upgrade. There is a single security issue mentioned in the release notes. Check all the fixes and changes that are listed on the release notes to see what issues are resolved and if you are affected.
I’ve compiled this version and did some simple tests on my test servers and it worked without any problems.
Please note that I’ve made some changes to the startup scripts to make sue that you are indeed running the updated version as indicated in my earlier post.
Read the documentation on how to ugrade MySQL.