There are two sides to STIR/SHAKEN. There's the network side, which we're more interested in, which is what we can do at the network level, blocking the calls before the consumer's phone even rings. Then there's what they refer to, which is the presentation layer, that checkmark or that notification to the end user on the phone that it's a blocked call.
There's a lot we can do to prevent the obvious stuff at the network level. Then the more fine-grained stuff will require new handsets and things such as that.