A new version of Tinderbox, Tinderbox 8.1, is out now.
You need Tinderbox 8.1 if you're using Catalina. But you don’t want to install Catalina if you don’t need it — not yet. This goes against my usual advice, because usually upgrading right away make everything better. Catalina has headaches. They’ll get fixed. And there's important stuff in Catalina, too, for the future. But if you don’t have to upgrade right now, wait a few weeks.
Tinderbox 8 has a big speed bump, especially if you're working with big and complicated documents. Opening documents, saving documents, adding new notes — it’s all faster. There are dozens of other improvements, too.