According to the announcement:
1.3.14 is now the only version that supports Windows 7, Windows Vista
and Mac OS X 10.4 to 10.7. Please upgrade to 1.3.14 if you are using
Audacity 1.2 on those systems. You can install Audacity Beta on the same
computer as Audacity 1.2 if you install to different directories. If you are
upgrading from a previous Beta release, you can install "over the top"
into the same directory.