Why is my app not launching on macOS 10.14 and below?

Unfortunately Apple has stopped supporting macOS 10.14 and below when it comes to developer tools. Due to this, we are unable to target 10.14 and below. When you try and launch the app on these versions of macOS, the app will terminate immediately.

Your only two options are to either downgrade the app and use the previous compatible release OR upgrade macOS to 10.15 or above. Here's a link to the last version that supported macOS 10.13 / 10.14:

https://storage.googleapis.com/downloads.2doapp.com/2Do-2.7.6-275128.dmg