Trick for separating Develop from Release versions in New Relic Mobile SDK.

build.gradle

...

android.applicationVariants.all { variant ->
    task ("prepareNewRelicProperties${variant.name.capitalize()}"){
        doLast {
            copy {
                from variant.buildType.debuggable ? "${project.projectDir}/src/debug" : "${project.projectDir}/src/release"
                into "${project.projectDir}"
                include "newrelic.properties.*"
                rename "newrelic.properties.*", "newrelic.properties"
            }
        }
    }
    tasks.getByName("prepare${variant.name.capitalize()}Dependencies").dependsOn("prepareNewRelicProperties${variant.name.capitalize()}")
}

newrelic.properties.debug

# should be located in src/debug
com.newrelic.application_token=MyNewRelicDebugApplicationToken

newrelic.properties.release

# should be located in src/release
com.newrelic.application_token=MyNewRelicReleaseApplicationToken

NewRelicSplitApplication.java

...
NewRelic.withApplicationToken(getString(R.string.my_new_relic_application_token).start(this);
...

strings_keys_debug.xml

<!--should be located in src/debug/res/values-->
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="my_new_relic_application_token">MyNewRelicDebugApplicationToken</string>
</resources>

strings_keys_release.xml

<!--should be located in src/release/res/values-->
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="my_new_relic_application_token">MyNewRelicReleaseApplicationToken</string>
</resources>