On November 17, 2023 beginning at 15:30 UTC the OpenDev team will upgrade Gerrit at https://review.opendev.org from Gerrit 3.7 to 3.8. This upgrade shouldn't take more than an hour. We have managed to to keep our Gerrit installation about one major release behind upstream's release cadence, and Gerrit 3.9's impending release means it is time for us to upgrade to 3.8.
There are a number of new features, bug fixes, and performance improvements in the new version. The Gerrit project publishes detailed release information  which you can review if you are interested in what sorts of changes to expect. If you are interested in the upgrade process you can follow that in our planning document . It is worth noting that if all goes well we expect the total Gerrit downtime to be much shorter than an hour (should only take a few minutes). If we need to revert to Gerrit 3.7, we will need to do offline reindexing of our changes which takes about half an hour. We are using an hour long upgrade window to ensure we have time for downgrades should that become necessary.