The intention from the start was to make upgrades to newer MySQL versions trivial. We have done a lot of work to keep data formats compatible (both in the .frm files and in the storage engines); when you install a new version of MySQL things should "just work". For a long time this was true, until MySQL 5.0 where we had to do some data incompatible changes, like in the way some characters were sorted and how end-of-line blanks were stored in indexes.
I've just pushed the last batch of changes into 5.2 tree. The most important change was renaming Maria engine to Aria(with old
maria* compatibility variables).
Dear MariaDB users, MariaDB 5.1.50, a branch of the MySQL database which includes all major open source storage engines, myriad bug fixes, and many community patches, has been released. MariaDB: Community developed, feature enhanced, backward compatible. For an overview of what's new in MariaDB 5.1.50, please see the release notes.
MariaDB 5.1.44b Linux and Solaris binaries, Ubuntu/Debian/CentOS packages, and source are now available for download. This is a bugfix/security release of MariaDB 5.1.44. From the MariaDB 5.1.44b Release Notes: