If you have just installed a new version of the Buildbot code, and you have buildmasters that were created using an older version, you'll need to upgrade these buildmasters before you can use them. The upgrade process adds and modifies files in the buildmaster's base directory to make it compatible with the new code.
buildbot upgrade-master basedir
This command will also scan your master.cfg file for incompatibilities (by loading it and printing any errors or deprecation warnings that occur). Each buildbot release tries to be compatible with configurations that worked cleanly (i.e. without deprecation warnings) on the previous release: any functions or classes that are to be removed will first be deprecated in a release, to give you a chance to start using the replacement.
upgrade-master command is idempotent. It is safe to run it
multiple times. After each upgrade of the buildbot code, you should
upgrade-master on all your buildmasters.
In general, Buildbot slaves and masters can be upgraded independently, although some new features will not be available, depending on the master and slave versions.