BuddyPress.org

Whew. OK, panic stations stand-down.

Here’s how I fixed it, hopefully without breaking anything. I renamed functions.php — that got me into the backend. I had to Network Activate Buddypress, then I renamed functions.php back again. All looks well on first glance.

I suppose I didn’t follow SOP with upgrades — I had thought that we had gotten to the point where automatic upgrading was ‘safe’ with BP.

Object lesson for others in future, I guess.