Yes it's hypothetically possible to update the software on orbit, and anything they need to do that could presumably be brought up on a Soyuz (I know there's one next week, but it's probably too late to get it on unless they've been secretly and frantically working on that for the last month).

But it's a lengthy process, not sure why (weeks) and the software used previously is not necessarily compatible with latest software currently on the ship for the manned flight. Maybe they need to time to update it for compatibility. Fluster Cluck.