It works fine if scanned by a machine though (ticket gate, self checkout etc.)
I've used a third party app for this for a UK weekly pass train ticket you could only buy physically, but if you buy it on a train rather than at a station they can't print you a ticket with a magnetic strip and they have to give you one with a barcode (technically an Aztec code), which you can then scan onto your phone and use at the gate. But I kept the original ticket with me too and would use that if a person asked to inspect it
T-Mobile had this issue 5 years or so ago where the IMS core went down due to fiber issues at one of their major backbone providers (pretty sure it was zayo).
As I've said elsewhere, never underestimate Verizon's incompetence. A couple years ago they shut down vtext service which also happened to host their UAprof's for most Android phones. Without a working link to these descriptors, those devices would download any MMS (pre-RCS picture messages) in compatibility mode at the lowest resolution.
reply