I purchased the standard license on 11-4-2019 and have an invoice to prove it. All worked fine until today, when I received the expired license message (pasted below) when I opened up BTT in the usual way. it won't let me open the app on my 2019 Mac Pro.
How can I resolve this?
Thanks, Matt
Your BetterTouchTool License doesn't cover this version of BetterTouchTool anymore 
Your license was purchased more than two years ago. The standard BeterTouchTool license includes free updates for two years. (Originally I announced it would cover only 1.5 years, but I have extended it to two years for all users)
However your license is still valid for all versions you received during these two years. You can now decide whether you want to use the last version of BetterTouchTool that was covered by your license, or whether you want to purchase a license upgrade and continue with the latest & greatest BetterTouchTool version.
It would be awesome if you'd decide to continue to support the further development of BetterTouchTool by purchasing a new standard or lifetime license. I just went self-employed and have many plans for the future development of BTT (and I'm sure you will like the upcoming updates).