It seems I am no longer able to use Papyrus Author due to my older Macbook Pro, which still works great after seven years and was recently boosted with a new battery installation. I am not in the market for a new laptop so it seems like I will no longer be able to use my Papyrus Author, meaning all of the 60,000+ word stories I have are now useless and unable to be seen due to the PAP files not opening in Papyrus and me getting the error message. I downloaded the newest version to try it anyways, but it doesn’t work with High Sierra, which I kept installed due to owning CS6 Photoshop and wanting to keep that working. Are my stories just lost forever? Why am I unable to at the very least open the stories and make them files that are readable elsewhere? Is there an older version of Papyrus I can download that doesn’t require constant internet connection? If not, I’m upset with myself for downloading Papyrus Author to begin with. Had I known it wouldn’t continue to operate smoothly without internet, I’d have stuck with LibreOffice.
Hi, sorry you ran into this!
Because of how Apple phases out support for older macOS versions, Papyrus Author eventually stops working on them as well. Here’s more info on this topic: 10.08a Incompatible with macOS Sierra (10.12.6)
If you’ve got another computer (macOS or Windows), you can move your projects over, continue there, or export them to Word files. I can help with that as well. 
Here’s a video on moving from Papyrus Author to Word: Word Documents II: Exporting Papyrus Documents to Word
You’ll find the projects in your “Documents” folder under “Papyrus Author Documents”.
I’ve also reached out with a private message to make sure you’ll get to continue your work–we’ll figure it out! 
Do you have a TimeMachine backup or some other backup copy of Papyrus that you could revert to?