Use Java 11 and Kotlin 1.4

[marandaneto]

'compileJava' task (current target is 11) and 'compileKotlin' task (current target is 1.8) jvm target compatibility should be set to the same Java version.

Since we support AGP 7.x+ https://developer.android.com/studio/releases/gradle-plugin#jdk-11
We can use Java 11 features and no need to add compat. to VERSION_1_8.
Same for Kotlin 1.5, No need to languageVersion = "1.3"
https://developer.android.com/studio/releases/gradle-plugin#incompatibility_with_14x_kotlin_multiplatform_plugin

[romtsn]

Should be done for 3.0 GA probably? just to make sure, even if it's breaking :)

[marandaneto]

Yes if possible, it's not breaking tho, since AGP 7.x requires Java 11, so requiring AGP 7.x is already the breaking change by itself.

[marandaneto]

Bumping to Java 11 lead me to this issue https://youtrack.jetbrains.com/issue/KT-48745

[cortinico]

Bumping to Java 11 lead me to this issue youtrack.jetbrains.com/issue/KT-48745

That is just a warning though, no?

[marandaneto]

Yes, but since there are many ways of setting source/target compatibility, plus language version compatibility on Kotlin etc, I was unsure of the correct way since the Warning was never gone, not a high priority for now, when Bumping to Kotlin 1.6, the warning should be gone anyways.