Updated to 10.13, iPhoto library won't load

I was using iPhoto 8.1.2 on my 10.9.5 system with a pretty large library. I got a new machine with 10.13, and used Migration Assistant to move my data. iPhoto (not Photos) on the new machine (v9.6.1) won't open the photos - it says "library must be updated", then gets about half-way (according to the progress bar) and quits with "Your photo library is damaged or unreadable". I know that iPhoto on 10.11 has no trouble updating and then opening it. What do I do to get it working on 10.13? I tried holding down option-command when opening iPhoto and selecting rebuild thumbnail, same result.