Is there a way to access plugin source code from JetBrains?

I'm currently using Emacs+ plugin on IDEA 2016.3.5 and I can't update to the latest version since the plugin doesn't work on that version. There are a few of us who use the plugin who have been trying to reach its author, but they have not replied to any of our queries for a while, and many of us are left on our own. I was just wondering since, if I understand correctly, the plugin is pretty much open source, do JetBrains have a copy of it that can be made available to the public?