Gradle tip - Always choose dependencies explicitly

For the sake of your CI process and versioning (the ability to go back in time in your SCM and get the same result) - always use explicit versions in your maven dependencies.

Do:

compile "some.library :21.0.3"

Don't:

compile "some.library :21.0.+"

Also, use the same gradle version (that can be easily achieved using a gradle wrapper) .