When starting a new project, it is generally recommended to go on the most recent version of MySQL, to take advantage of the latest features but also (mainly?) to be sure to be up to date with the security patches.
This blog post centralizes the various URLs where to download the world’s most popular open source database.
I regularly meet with MySQL customers and I’m still a little surprised to see critical applications running on “not really” recent versions (to put it mildly) 🙂
The good news is that obviously old versions of MySQL are sufficiently stable and powerful to run the modern business. However, even if I understand that it is sometimes appropriate to freeze all layers of an architecture, it is often a shame not to take advantage of the latest improvements from a performance, stability, security point of view and obviously for the new features that the latest GA provides :