You need to uninstall CC 2015 and then magically the "Previous versions" will appear in the Creative Cloud app in the relevant section.
Hmmmm... I think there's another way to do it that doesn't involve uninstalling AE CC 2015. Check out this link:
There's a section called "Download previous versions". You can have both versions on your machine... although the 2014 version works a heck of a lot better.
Dave LaRonde wrote:
You can have both versions on your machine... although the 2014 version works a heck of a lot better.
Maybe, maybe not. On my machine at home, CC 2015 runs smoother (and actually, on some projects, renders faster - which makes no sense). I use it exclusively now except for final renders.
And yes, you can install CC 2014 (and CC and CS6) without uninstalling CC 2015. Dave's link explains it as does this one: How to Find and Install Previous Version of Adobe Apps in CC 2015