It was "fun" discovering this the hard way a number of years ago when active US Android user count for a game we were supporting dropped 15% essentially overnight. The TCP stack in the client only did IPv4.
The challenge, ironically, was convincing management that adding IPv6 was the thing worth trying. After almost a week of getting nowhere (and almost 2 weeks of outage), I forced the issue by saying "Look, I'm doing this. I need one engineer for 2 days. If it doesn't work, then it doesn't work."
He got the change implemented in 2 hours. QA OKed it the next day. The topic never came up again.
I have AT&T Fiber and it's been /64 since forever. I even called tech support who confirmed that they only provide /64 prefix length to home customers. How come did you manage to get a /56?
Sorry I confused prefix delegation with with having an allocation. I have multiple /64’s. It looks like with PD you can have up to 16 subnets, so equal to a /60.
My experience is different: Comcast has been doling out IPv6 addresses for at least a decade, at least in San Francisco.
My T-Mobile phone gets IPv6 addresses.
My work and my swim club also have IPv6. It's pretty awesome.