First of all, thanks a lot for a wonderful library.

I myself started trying to upgrade to Gradle 8.6, but I am inexperienced and there seems to be a lot of details and deprecation warnings that I do not know how to fix.
I think that this library is intended to be able to be used with very old JDK versions (like 8). Is that also a problem while trying to upgrade the gradle build?

Edit: This paste https://pastebin.com/vkXXLmUR contains the build.gradle (with very little modifications, and possibly in the wrong place), and the output of
$ gradle build --warning-mode all
using current gradle 8.6 (using JDK 17.0.9 on macOS).

@mperry , @jbgi , @gliptak , and other contributors?