Some suggestions. One Critical!

Found the app very useful on my laptop - on the computer its fantastic! However on my iPad Pro it remains unused. This is purely based on the fact that highlight sync does not work between devices. This is a major issue for me. Also Apple Pencil support would be nice :) would change to 5 stars if these features were available.

TRRosevelt3 about Bookshelf, v3.8.1