Lauren, here's a fairly simple but wide-ranging review for you. It just removes a lot of temporary backwards compability code that isn't needed anymore. It touches five packages, and you can find the changesets in the GitHub PRs linked from the issue page.

Note that this is just one part of a larger issue (DM-1766), and I plan to hold off on merging it (even though I think it should be safe to merge) until the other subtasks are done and reviewed as well (but I'll ask other people to review the other things).

Oops, just found another package that needed changes, meas_modelfit (changes there are extremely simple).

This looks good to me, although it's difficult to assess if anything has been missed or is in err with no way to test (and very little familiarity with the old version!). I assume you will run Buildbot once all the necessary subtasks are in place before doing any merging, so I'm happy with the work here (but do see my minor comments in the PRs).

I'm marking this as done because I've made all requested review changes, but it has not yet been merged to master - I'm making the changes on tickets/DM-1766, which I'll merge once all subtask issues have been reviewed. In the meantime, I'll keep the original subtask issue branches as they were to keep the all of the review diffs from changing constantly.