If you are running OS X 10.7 to 10.10 (Yosemite), you should run the current official release of Sente, which can be downloaded here:
Download: Sente 6.7 for Mac (zip file)
Sente for iOS (iPhone and iPad) is available for free through the Apple iOS App Store.
Download: Sente 6.7 for iPad (via the app store)
We strongly encourage all users to upgrade to the most recent version of Sente and we only provide limited support for earlier versions. However, some users have special circumstances that prevent them from upgrading to the latest version. For these users, we make some older releases of Sente available here for download.
If you are running OS X 10.6, and therefore cannot run Sente 6.7 (which requires 10.7 or higher), you can run Sente 6.6, which is compatible with Sente 6.7 on both the Mac and iPad. (That is, you can run Sente 6.6 on one or more machines, and Sente 6.7 on others, and share synchronized libraries across all of these devices.)
Download: Sente 6.6 (for OS X 10.6) (zip file)
We no longer support Sente 6.5 and earlier.