Do they do all this testing for all GSM phones in the world? All new and old? All GSM phones ever sold?
I guess not. I guess instead they rely on the GSM specification to allow seamless independence between the phone and the carrier for 99.999% of the phones out there (if not more).
So why do they need to "test" the remaining 0.001% when they have a update in user-facing functionality the carrier will never see or interoperate against?
No carrier in Europe does this.
Does your ISP control what OS updates you can download? No. And why should they?
That carriers needs to do testing is a lie perpetuated to allow for customer-hostile business-practices. Stop repeating it.
It happens with Apple OS updates too, Apple just have sufficient market clout to tell networks they must complete the testing in the week between the gold master release and the public release.
GSM isn't some magic specification. It's entirely possible for a crappy radio firmware to cause significant disruption to a network it connects to (indeed, I've seen a pre-release firmware from a mid-tier Android manufacturer that managed to cause a reboot in every cell tower it connected to from one of the UK's networks). That's an extreme example, but carriers frequently do testing on that basis, and it often holds up the European releases of Android software updates.
I guess not. I guess instead they rely on the GSM specification to allow seamless independence between the phone and the carrier for 99.999% of the phones out there (if not more).
So why do they need to "test" the remaining 0.001% when they have a update in user-facing functionality the carrier will never see or interoperate against?
No carrier in Europe does this.
Does your ISP control what OS updates you can download? No. And why should they?
That carriers needs to do testing is a lie perpetuated to allow for customer-hostile business-practices. Stop repeating it.