BETA versions are pre-release versions. They are untested, unverified and are not official release versions. BETA versions are for users to test to see if a bug that is affecting them has been fixed. They may also contain new features or changes that some users may want to test first.
If you find a bug in a beta version, please submit a support ticket with details (please do not forget to include the BETA version number). BETA versions are sometimes released frequently, even hourly.