The top-of-rack Montreal power redundancy maintenance is taking place today within the timerange noted in in the email you received. We will update this posting upon completion, or if we need to share any intermediate details.
This work is complete and everything in Montreal is online.
We're going to have to reload the switch operating system for servers in series srv71xx. This will unfortunately extend beyond the outage window. We'll update this posting as we have more details, but we don't expect it to take very long.