On March 23, 2019, Apple finishes the review of version 12.1.12 of PDF Notes S and it became Ready for Sale.
On March 22, 2019, I uploaded version 12.1.12 of PDF Notes S to App Store
App Store https://itunes.apple.com/app/id961336139
This version fixed bugs, and supports 8 configurable writing tools including pen, highlighter, sticky notes, text, text highlight, text strikeout, text underline, square, circle, line.
It also supports more keyboard commands including tab, shift-tab, undo(command-z), redo(shift-command-z). And there are many other enhancements...