The tournament files are backwards compatible, not forward compatible. This means that you should always be able to load a tournament saved from a previous version of the software (backwards compatible), but you may not be able to load a tournament from a newer version.
For example, using version 2.2 you should be able to load tournament files saved with version 2.1.2, 2.1, 2.0, or even 1.3.5. But using version 2.1.2, you can't load tournaments saved from a newer version, such as 2.2.