I'm running Aquamacs 3.6 on a Mac running macOS 11.6. I've been happily running org-mode 9.1.14 for years. Today, for no particular reason, I tried to upgrade to org-mode 9.5. I was able to upgrade, and org-version changed to "9.5", but when I tried some simple commands in an org file, like "TAB" to do an "org-cycle", I got
cannot open load file, no such file or directory, backtrace
When I looked in the *Messages" buffer, I saw
Error during redisplay: (jit-lock-function 1001) signaled (void-variable org-element-citation-prefix-re)
Error during redisplay: (jit-lock-function 1501) signaled (void-variable org-element-citation-prefix-re)
eval-buffer: Cannot open load file: No such file or directory, backtrace
Warning: Bug in org-mode: it forgets to call `run-mode-hooks'
Cannot open load file: No such file or directory, backtrace
Mark set
For now, I've gone back to version 9.1.14, which still works. What might be wrong?