MacRumors reports hearing from several iPhone users—and relatives of users—who have begun to notice that some key functions are simply gone. People on the AppleVis forums are also talking about the now-missing features, noting that this creates a problem for visually impaired users who regularly use them. The issue isn’t tied to a specific version of iOS or model of iPhone either, so whether it’s intentional or a glitch of some kind it seems to be specifically happening through Siri.
Apple
Siri's list of missing functions includes being able to ask about voicemails, playing voicemails, checking call history, and sending emails.