Specifically, I am interested are new line 4.x commons-collections library backward compatible with 3.x version.
From the release notes for 4.0 version:
To help with the migration to this new version, the package has changed to "org.apache.commons.collections4", thus it is possible to have both commons-collections versions in the classpath.
Source: https://commons.apache.org/proper/commons-collections/release_4_0.html
This means that you can include both versions in your classpath without name collisions.