Adobe maintains compatibility within major release versions of Premiere Pro.
Within a major release, project files are forward and backward compatible: you can open and save any Premiere Pro v15.x project with any 15.x version of Premiere Pro – including Dynamic Link with After Effects 18.x versions.
If you open a project from a previous version, Premiere Pro 15.x will save the original project and create a new 15.x project file.
If you have opened your project in the latest version of Premiere Pro and want to revert back to using the previous version, save the file in XML format and import it in the previous version.
Check out this video to learn more.
Viewing time: 32 seconds