Though AT&T had Wi-Fi calling enabled through much of the iOS 9 beta program this summer, those who upgraded to the final version found that the feature was missing. The reason? It doesn’t support teletype services (TTY) for the deaf and hard of hearing very well, which the FCC generally requires of wireless networks. In its place, AT&T wants to deploy real-time text (RTT), which it says is faster, richer and generally better than TTY — a decades-old technology.
That roadblock has been cleared now with a waiver granted by the FCC that lets AT&T get around the RTT rule until the end of 2017. (AT&T doesn’t yet have a time frame for flipping the switch back on for customers, but it shouldn’t take long.)
This article originally appeared on Recode.net.