Likely two windows. (1) Developer boxes, then (2) production including oris-srv04 and si-taverna. si-ft1 can be done any time and no one will notice. I like doing a cursory test on our test environment before doing production though I have not had any recent problems.

For production, we have to drain down the ingest pipelines and that can take a day but 2 days is not unusual. And I generally do the actual production update outside normal working hours.