Hello. I'm gearing up to migrate several CF 2016 servers to CF 2021. Is there an official migration guide? I found a link to one but the file no longer exists. I also found a link to @carehart’s great PowerPoint migration guide in PDF form. Any others? Thanks in advance.

There is not...well, there's a guide for each version (not crossing versions), but even that is focused more on migration of the CF admin settings. It does NOT cover migration of code. My talk (PDF or video, at carehart.org/presentations) was my attempt to address that lack (and as you may have seen, I go into a LOT of detail on migration issues, in code and otherwise). I point also there to some other resources, but I guess you assessed those. Not much more, I'm afraid.

Thanks Charlie! I think I have what I need. I appreciate it.