What I ended up doing is trying the General Update first, but it didn't appear to "take", i.e. nothing was reported installed. So I reinstalled Delphi XE8, then installed the General Update and that appeared to work, at least so far.
I installed XE8 when I had an active subscription. Since that I had to let the subscription expire, and it looks like 1 update came out since. There is a general update and a subscription update, and it says Delphi will have to be reinstalled if we use the wrong update. It's not clear which update is correct for me, since my subscription expired after initial install of XE8. Can someone clear it up for me?