Greetings: The Cinder project has two new stable releases: - 16.2.0 (Ussuri) - 15.4.0 (Train) (we also have a new Stein, 14.3.0, but it's not relevant to this discussion) Among other things, these address Bug #1893107 [0], which could prevent a cinder database upgrade from Train to Ussuri when the database in question had been (a) unpurged and (b) originally upgraded from Stein to Train. (A purged Stein database upgraded to Train, or a database that was new in Train, would not be subject to this issue.) The 16.2.0 [1] and 15.4.0 [2] release notes outline some strategies for addressing this issue. We recommend that you read both before attempting an upgrade to Ussuri and decide which strategy works best for you and your users. (Of course, you always read all the release notes, but we figured it wouldn't hurt to bring this particular point to your attention.) Thank you for your attention to this matter! [0] https://bugs.launchpad.net/cinder/+bug/1893107 [1] https://docs.openstack.org/releasenotes/cinder/ussuri.html#relnotes-16-2-0-stable-ussuri [2] https://docs.openstack.org/releasenotes/cinder/train.html#relnotes-15-4-0-stable-train