@mavens

Software Developer

Active Stack Overflow contributor specialized in Android, Java, Kotlin, and Gradle topics. Holds many gold badges.

https://stackoverflow.com/users/1761003/mave%C5%88%E3%83%84

Mobile Dev Fix Kotlin Unit Error Metadata 2.1.0 vs Compiler 1.9.0 in Android Studio

Resolve 'kotlin.Unit' incompatible version error in Kotlin Android Studio after adding Firebase Cloud Messaging Java service. Upgrade Kotlin to 2.1.20, align Gradle, AGP, Java 17 for firebase messaging compatibility.

#android
#android-studio
#firebase
#gradle
#kotlin

3 answers• 1 view

02/27/2026, 05:30 PM