I mentally swap the labels[1] when reading their marketing or release notes. If it says things like "No longer crashes when using IPv6", then I flip that and read it as "No longer crashes when using IPv4". That latter statement is absolutely insane and would have you abandoning that vendor as fast as you can tear up the contract. Nobody bats an eye with the first statement! Why not!?
Azure literally had this scenario, where merely enabling IPv6 on one network would crash their managed PostegreSQL service on another peered network with no recourse other than rebuilding everything form scratch without IPv6 to roll the change back!
[1] Or a generic placeholder than encompasses both. E.g.: "Fix: Enabling the internet protocol no longer causes irreversible outages with your database service."
Even Google, one of the champions of IPv6 adoption on the Internet, only started adding IPv6 support to GCP in the 2020s. In all public clouds, there are still numerous services that don't support it at all. And I can 100% guarantee that the next public cloud that anyone creates will start off with IPv4 support; maybe it will have IPv6 as well on day one, maybe not.
On the contrary, essentially all of the IPv4 public ranges have now been allocated. The incumbents have bought up what they can, leaving essentially nothing for new clouds to use. It's one type of moat, and the three biggest providers are happy to keep everyone on the far side of it.
A new cloud starting in 2025 onwards would likely be based on an IPv6 native design with IPv4 as the "add on" for public endpoints only, such as load balancers and proxies.
IPv4 is far too ingrained to start with IPv6 only.
We’re closer than most people assume.
If ipv6 had been designed form the start to allow seemless transparent access to ipv4 from an ipv6 only client that would be fine. But dual stack means twice the work and very little benefit (what services are ipv6 only, even today)
It does. It's called NAT64, and it works/breaks as well as regular NAT44.
A good majority chunk of cell carriers today have gone IPv6-only for phones. They rely on NAT64 gateways (rather than CGNAT) to access IPv4-only resources. A lot of consumer internet is slowly following that lead as a better alternative to CGNAT. At least if your customers are consumers we are really close to "You might only need to serve IPv6."
(It's the "Enterprise-grade internet" that is interestingly lagging and falling behind in IPv6 adoption, and maybe doesn't see enough reason to support IPv6-only well; especially if the cost of IPv4 plateaus again, as some suggest it might. Recent AWS cost increases for IPv4 have been something of a call to action to some Corporations, but in general if you are B2B you probably need IPv4 support for a while longer as the economic incentives games play out on a long, slow horizon.)