I have not been able to play on my own server since the update.
I have done as requested which is;
Delete the mods folder
unsubscribe from all mods
verify game files (checks out OK)
Delete mods folder
deleted and reinstall server
added only add mods that are 1.7 compliant.
ran the server and when the client connected they downloaded the mods and I still get the error.
I have also gotten this error on community servers.