IONIC- Dex: Error converting bytecode to dex:- targetCompatibility = '1.7' sourceCompatibility = '1.7'

Question

targetCompatibility = '1.7' sourceCompatibility = '1.7'

   Dex: Error converting bytecode to dex:
Cause: Dex cannot parse version 52 byte code.
This is caused by library dependencies that have been compiled using Java 8 or above.
If you are using the 'java' gradle plugin in a library submodule add
targetCompatibility = '1.7'
sourceCompatibility = '1.7'
to that submodule's build.gradle file.
    UNEXPECTED TOP-LEVEL EXCEPTION:
java.lang.RuntimeException: Exception parsing classes

Please help, facing issue with Ionic 3