I have an app that has as minSdkVersion API 14, I've tested the app on a device running Android M and everything works fine, then I've tried to run the app on a device running API 15 (Android 4.0.3) and I get the following crash when the app starts:
FATAL EXCEPTION: main java.lang.NoClassDefFoundError:
com.google.firebase.FirebaseOptions 
at com.google.firebase.FirebaseApp.zzbu(Unknown Source) 
at com.google.firebase.provider.FirebaseInitProvider.onCreate(Unknown Source) 
at android.content.ContentProvider.attachInfo(ContentProvider.java:986)
at com.google.firebase.provider.FirebaseInitProvider.attachInfo(Unknown Source) 
at android.app.ActivityThread.installProvider(ActivityThread.java:4249) 
at android.app.ActivityThread.installContentProviders(ActivityThread.java:4004) 
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:3958)
at android.app.ActivityThread.access$1300(ActivityThread.java:127) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1197)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4507)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
at dalvik.system.NativeStart.main(Native Method)
I'm not using Firebase in my app and this is my gradle:
apply plugin: 'com.android.application'
android {
    compileSdkVersion 23
    buildToolsVersion "23.0.3"
    defaultConfig {
        applicationId "it.*.*"
        minSdkVersion 14
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
        multiDexEnabled true
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}
dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.4.0'
    compile project(':libraries:Sliding Menu')
    compile 'com.android.volley:volley:1.0.0'
    compile files('libs/YouTubeAndroidPlayerApi.jar')
    compile 'com.android.support:cardview-v7:23.+'
    compile 'com.squareup.picasso:picasso:2.5.2'
    compile 'com.android.support:design:23.4.0'
    compile 'com.google.android.gms:play-services-analytics:9.0.0'
    compile 'com.google.android.gms:play-services:9.0.0'
    compile 'com.android.support:multidex:1.0.1'
}
apply plugin: 'com.google.gms.google-services'
Does anyone know what could be the problem? Why is it crashing only on the device with API 15?