Release Notes
https://github.com/kiwidude68/calibr...en_with-v1.8.4
This one is for the couple of users who have reported out of memory errors when trying to use this plugin to open with Adobe Acrobat. I have no clue of the real cause other than subprocess.Popen() with an arg array triggers it but constructing a single command line works. So back to the old way of launching apps.
Which might break something else for some edge case but it is what it is at this point... use the built in book details pane functionality that calibre has nowadays instead...