There are two releases of Cedar Backup: version 2 and version 3. This project (Cedar Backup v2) uses the Python 2 interpreter, and Cedar Backup v3 uses the Python 3 interpreter. Because Python 2 is approaching its end of life, and Cedar Backup v3 has been available since July of 2015, Cedar Backup v2 is unsupported as of 11 Nov 2017. There will be no additional releases, and users who report problems will be referred to the new version. Please move to Cedar Backup v3.

The main difference between Cedar Backup version 2 and Cedar Backup version 3 is the targeted Python interpreter. Cedar Backup version 2 was designed for Python 2, while version 3 is a conversion of the original code to Python 3. Other than that, both versions are functionally equivalent. The configuration format is unchanged, and you can mix-and-match masters and clients of different versions in the same backup pool. Both versions will be fully supported until around the time of the Python 2 end-of-life in 2020, but you should plan to migrate sooner than that if possible.

A major design goal for version 3 was to facilitate easy migration testing for users, by making it possible to install version 3 on the same server where version 2 was already in use. A side effect of this design choice is that all of the executables, configuration files, and logs changed names in version 3. Where version 2 used "cback", version 3 uses "cback3": cback3.conf instead of cback.conf, cback3.log instead of cback.log, etc.

So, while migrating from version 2 to version 3 is relatively straightforward, you will have to make some changes manually. You will need to create a new configuration file (or soft link to the old one), modify your cron jobs to use the new executable name, etc. You can migrate one server at a time in your pool with no ill effects, or even incrementally migrate a single server by using version 2 and version 3 on different days of the week or for different parts of the backup.