It had been in the works for a while, but now it has formally been adopted. From the article:
The regulation provides that by 2027 portable batteries incorporated into appliances should be removable and replaceable by the end-user, leaving sufficient time for operators to adapt the design of their products to this requirement.
There were waterproof phones and replaceable batteries concurrently but I don’t think this is requiring batteries to literally be hot swappable. I think as long as you can remove the back and the battery with regular common tools, nothing proprietary, that would suffice.
It would be harder to do an IP68 rating with a hot swappable battery. Although having hot swappable battery is a huge advantage anyway. But I don’t think that’s the requirement here, just so normal people will be able to get the battery out with a screwdriver but not necessarily in 3 seconds so they can replace a battery while they’re out and about
All of that said companies exaggerate the benefits of an IP rating. All of these phones are water resistant, not waterproof and even then water damage is almost never covered by the warranty. An IP ratings are only tested once under optimal conditions, in real life the IP rating isn’t going to hold up after heavy use or one single submersion in water anyway.
So I tend to think the benefits of IP ratings are wildly overstated. Even phones without them hold up pretty well when submerged in water briefly like the Pixel 4a or the OnePlus 7 or the s20 FE.