Sorry for any confusion. For you to access your shared controllers, your account needs to be on the same version as the controller shared with you. That does mean your customers need to upgrade to restore your access.
That being said, for our pros with 5+ controllers shared, we are assisting the upgrade of their customers this morning (acutally as we speak!). I believe you received an email about this, but if not, I apologize. Your access (and all pro access) should be restored by the end of today.
I’m sorry for any inconvenience.