It is well understood that IOS-XE does not support voicexml and thus MVA. Now that Cisco has and end of sale for the 39xx and 29xx routers, what is the path for those customers still wishing to use MVA or MVA like functionality in a world of ISR 4xxx voice gateways?
Specifically I am looking for something that provides a method to challenge/authenticate a user dialing in and then give them similar functionality as MVA would provide.