Ah, I think I was unclear – iOS and Android phones don't support updating these profiles via SMS anymore in the way that some older feature- and smartphones did.
The first time a network would see a new device (or after a long period of inactivity), it would send these out automatically, which was mostly useful but at times annoying when switching phones regularly.
There was usually also a way to manually trigger them, like sending a certain text (e.g. SETUP) to a short code.
Of course iPhones and Android smartphones still need APN and MMS data to function correctly, but these days that data seems to be part of the OS. In my view, that's a step back – I've had to get onto Wi-Fi to look for the correct APN for a travel SIM more than once. Arguably, it should be part of the SIM these days, just like the SMSC configuration.
The first time a network would see a new device (or after a long period of inactivity), it would send these out automatically, which was mostly useful but at times annoying when switching phones regularly.
There was usually also a way to manually trigger them, like sending a certain text (e.g. SETUP) to a short code.
Of course iPhones and Android smartphones still need APN and MMS data to function correctly, but these days that data seems to be part of the OS. In my view, that's a step back – I've had to get onto Wi-Fi to look for the correct APN for a travel SIM more than once. Arguably, it should be part of the SIM these days, just like the SMSC configuration.