JUCE is an open-source cross-platform framework for developing applications and plug-ins, especially for DAW applications. While it has built-in support for multi-touch on operating systems that have native touch support, such as Windows or iOS, it doesn't currently support multi-touch on macOS. Consequently, we've made an addition to JUCE that implements multi-touch on macOS for systems that have installed the UPDD and submitted it as a pull request to the JUCE GitHub repository. We hope that the JUCE development team will eventually incorporate these changes into the library officially.
In the mean time, it's fairly simple for a JUCE developer to include these changes in their application or plug-in. All that's necessary is changing a few files in JUCE's source code. This can be done by applying a patchfile to your local JUCE installation, or by checking out the pull request from the JUCE GitHub repository.
Afterwards, if you're running UPDD Commander, you'll need to configure it to skip gesture processing for touches that fall within your application and instead pass the touches along directly.
More information is available in the JUCE integration document, including showing how to configure JUCE based DAW plugins with UPDD Commander.