[Koha] Package upgrade to 3.22.11

Running a multi-tennant installation of Koha 3.22.10 on Ubuntu 14.04.5... I came in this morning to upgrade our package installation of 3.22.10 --> 3.22.11. Everything seemed to go okay, but when I tried to log on to Koha, I was directed to the installer interface. What did I miss? There was a message about koha-plack requiring additional modules (headers & proxy_http), but my understanding was that plack didn't yet work on Ubuntu 14.04... gcb