I have AE CC 2015. I had one compositor working in this environment and the project is saved for this file. I had to bring in another compositor working on his machine but the only has CS6. I can back save to CC 12. But I need someone with CC 12 to back save this to CS6. I've read that this is the only way this can work. Please help.
You may install a previous version
Previous via Cloud http://helpx.adobe.com/creative-cloud/help/install-apps.html#previous
-and difference if you have Cloud application manager 2015 https://forums.adobe.com/thread/1906752
Thank you John! That seems like a great answer and I had not known this was possible. However, after installing CC12, it will not open on my mac! I have El Capitan 10.11.1! Any advice? I'm going to try a reboot.