BiblioCraft v2.4.2 just released! I updated for the newest version of forge which changed out the registry and stuff. The previous version will crash with the newer version of forge, so this update fixes that. This should be compatible with the recommended build of forge for 1.12 that is coming out tomorrow as well.
Unlikely I will be able to get a chance to work on 1.8.9. It seems like 1.8.9 version was missing some stuff I needed too for some of the fixes I did in newer versions. Also it is hard enough trying to keep up with the 1.10, 1.11, and 1.12 now. I am honestly hoping everyone moves to 1.12 in the coming months. I want to be able to have time to actually add some new features soon instead of spending all my available time to work on BiblioCraft just updating multiple old versions.