You may have noticed it on your dashboard: Dotclear 2.1.7 is available. To make a long story short: if you plan to use the auto-update procedure, go for it. If for any reason you plan to update manually, forget it.
There is nothing new in the 2.1.7 but an update to the auto-update procedure (sic.) It was necessary because the upcoming 2.2 release has changes that cannot be handled by the auto-update procedure as we knew it. You won't be able to auto-update directly from 2.1.6 to 2.2!
Once again, if you plan to manually install the 2.2, you don't have to bother about the 2.1.7.
See you soon.
Update: It appears that because they were not expecting this maintenance release, some plugins may cause problems because they make the wrong assertion that this is the 2.2 already. Please consult the forum dedicated thread before upgrading..