I updated from 1.5~ to 1.7.2 EXCEPT it turned out it wasn't 1.72 (I swear to you I correctly hit the correct download button on the correct page for Macs) --it turned out to be 1.6.2.
I tried again a week or so later and was able to download & install 1.7.2. Unfortunately there was no brush sensitivity, everything was very blobby or similar width strokes. Okay. Some other stuff wasn't working as well either. Figured it must be my fault for not updating my tablet driver, downloaded an updated version, installed --nada, really bad brush marks. At this point I was desperate just to be able to draw something, so I trashed version 1.7.2 and reinstalled 1.6.2 ---which had better brush sensitivity but it's still not quite as lovely as my old 1.5.~ version everything.
Anyway, I ended up making my own "pain" marks. It was faster & I like them better I suppose.
Thank you for your help. Perhaps I will go ahead & download the materials folder.