In case you missed it, Bluebeam has stopped development on future versions of Bluebeam Revu for Mac.
UPDATE - As promised, Bluebeam issued an update in December 2019 as Revu for Mac 2.1 which includes support for mac OS Catalina and other bug fixes (click here to see release notes on the Bluebeam web site). They are stating that they will not release any new updates after March 2020, with the official end of life for the product being March 1, 2020. Note that they do state that your licenses will continue to work after that date, but there will not be any more updates or releases, including bug fixes and security updates.
If you need more information, you can read the full press release by Bluebeam by clicking here.