Answers for "fit requested classes in a single dex file (# methods: 68535 > 65536)"

D8: Cannot fit requested classes in a single dex file (# methods: 85258 > 65536)

defaultConfig {
    ...

    multiDexEnabled true
}

Cannot fit requested classes in a single dex file (# methods: 65710 > 65536)

android {
    defaultConfig {
        ...
        minSdkVersion 21 <----- *here
        targetSdkVersion 26
        multiDexEnabled true <------ *here
    }
    ...
}