From what I can tell, the telcos are implementing it, or at least say they are: * "Caller Verified is T-Mobile’s implementation of the STIR and SHAKEN standard

From what I can tell, the telcos are implementing it, or at least say they are: * "Caller Verified is T-Mobile’s implementation of the STIR and SHAKEN standards" [0] * "Verizon reiterates both our commitment to deploying the STIR/SHAKEN call authentication technology" [1] * "Sprint supports efforts to build the SHAKEN/STIR call authentication system" [2] * AT&T doesn't seem to mention STIR or SHAKEN by name on their robocall page [3] but the FCC sent them a letter thanking them for their "commitment to implement a robust call authentication framework in 2019" [4] * "Comcast is proud to be at the forefront of efforts to address the scourge of illegal spoofed robocalls in this country, including the development of the end-to-end call authentication protocol known as SHAKEN and STIR" [5] etc [0]: https://www.t-mobile.com/news/caller-verified-note9 https://www.t-mobile.com/news/caller-verified-note9 [1]: https://ecfsapi.fcc.gov/file/1119062987519/2018%2011%2019%20Verizon%20Call%20Authentication%20Framework%20WC%20Docket%20No.%2017-97.pdf https://ecfsapi.fcc.gov/file/1119062987519/2018%2011%2019%20... [2]: https://ecfsapi.fcc.gov/file/1091391175368/Sprint%20Call%20Authentication%20Comments.pdf https://ecfsapi.fcc.gov/file/1091391175368/Sprint%20Call%20A... [3]: https://about.att.com/sites/cyberaware/ae/robocall https://about.att.com/sites/cyberaware/ae/robocall [4]: https://docs.fcc.gov/public/attachments/DOC-354933A2.pdf https://docs.fcc.gov/public/attachments/DOC-354933A2.pdf [5]: https://ecfsapi.fcc.gov/file/111974588343/Comcast%20Resp%20to%20Chmn%20Pai%20re%20SHAKEN%20STIR%20(11-19-18).pdf https://ecfsapi.fcc.gov/file/111974588343/Comcast%20Resp%20t...