Failed to build project that pull appcompact dependencies, but not say why

Extracted your project fresh, I get this:

               -> Task RemObjects.EBuild.Elements.ElementsPreflightAndroid started for FireApp.
                  Android SDK found in '/Users/mh/Library/Android/sdk'.
                  Android Build Tools found in '/Users/mh/Library/Android/sdk/build-tools/28.0.0-rc1'.
                  Android ApkBuilder found in '/Users/mh/Library/Android/sdk/tools/lib/sdklib-26.0.0-dev.jar:/Users/mh/Library/Android/sdk/tools/lib/sdk-common-26.0.0-dev.jar:/Users/mh/Library/Android/sdk/tools/lib/common-26.0.0-dev.jar'.

...

                  dex> processing org/me/fireapp/R$string.class...
E:                dex: com.android.dx.cf.code.SimException: ERROR in com.elmalabarista.mamcx.droidui.UIBuilder.view:()V: invalid opcode ba - invokedynamic requires --min-sdk-version >= 26 (currently 5)
                  dex> 1 error; aborting

I se min-sdk to 26 and sdk to 27 and still get the error if I set the repo from fire:

<GradleRepository Include="https://jitpack.io" />
<GradleRepository Include="https://maven.google.com/" />
<GradleReference Include="com.github.vic797:prowebview:2.2" />

But it compile when using android studio to build the JAR and reference it locally. I will report back if this work fine.

Well, your test case project didn’t have these. I can only test against the info I have. You project, as you posted it gives me the above error, and compiles fine if I change the Minimum version up to 26, as the message tells me.

If you can send me different test case, I can have a look at that.

Yeah, I know that. I just point that is a fix that look like is not general.

And for the test case is the same project, with different gradle references (as show).

I need the exact project; I cannot look into issues like this if I have to guess what changes I might need to make to a project I have for the error to show up. The last case, as I have it, builds. If a changed version exhibits a different bug/error, then I need that version as new testcase.

—marc