IMCE icon not displaying on CKEditor

Having the same issue. Pantheon's autopilot updated to version 3.1 on several of our sites, and now the imce button is no longer available to add to CK Editor. Sites still using version 3.0.11 work fine. Nothing in our configuration changed, the imce button is simply no available to add to CK Editor. Not seeing any js errors.

So I see now the issue is that you've stopped supporting CK Editor version 4, which is unfortunate because CK Editor 5 is FAR from ready for prime time. It's also bad practice because you've broken, I'm sure, hundreds of production sites.
Please consider re-instating CK Editor 4 support.

Use 3.0.x for CKEditor4 support.

Added a description to download section.