Comment 8 for bug 1943292

We needed to decommission our powerpc builders first, because the logistics of running builders on both xenial and focal were going to get a bit much (we had a hack to make it work for riscv64, but it was a pretty awkward and confusing one). That was completed last week.

The next obstacle is getting launchpad-buildd's test suite working on focal, which it seems we'd neglected to do up to now and there are a few small problems. Once that's fixed I expect we should be able to upgrade the whole build farm to focal fairly quickly; I ran some small-scale tests of this a month or two ago and things seemed mostly fine.