The developer beta build is 19A5261w as well!
Same with me, I still have direct access through the iOS Dev portal as I used to pay years back. I thought it might have been a fluke, but it looks like they just don’t stop access to some of the tools.
On iOS 15. It has been very stable for me. I prefer how notifications have changed but Safari is a pain. Luckily, I don’t use it that much.
I have/had an issue with iCloud+ Relay stopping my internet at times but that seems to have settled down and more on macOS Monteray.
One thing I have found is better is the stability of activating hotspot from other devices. On iOS14 activating hotspot on my phone from my iPad was a bit dodgy but working perfectly now!
Builds are the same, just one group gets them before the other.
You’ll see this yourself, usually when the public betas get involved. They’re the same build too, more often than not, they’re just pushed out last after Appleseed and developers have had a week or two to play with them, all other things being equal.
I agree with you completely, generally developer and Appleseed track with identical builds released at the same time, although they use different profiles. Clearly this would allow them to diverge if it was thought necessary.
It is the public beta that is generally a week behind, with the same build but released later. This is to allow for emergency fixes, if needed, before the public receive a build - but that actually happening is very rare. On the rare occasion it does happen, an updated beta is usually then released for beta/Appleseed at the same time to sort the issue.
The exact timing of the “public delay” varies depending on where in the beta process the current testing release is (towards the end the delay will often be only hours, for more stable builds, compared to days). At this time of year, around WWDC, the first few betas are always developer only and the public beta track often continues on a x.x beta track for an upcoming summer point release. This is what happened last year, and it’s currently happening again with iOS 14.7 now in testing simultaneously with iOS 15. Developers could also be testing iOS 14.7, with the iOS 14 profile, but obviously Apple is not expecting them to test it extensively as they focus their attention on iOS 15. The public beta users are therefore ideal at filling the gap.
TL;DR there are three tracks to the betas: public, AppleSeed and developer. Developer and AppleSeed are almost always identical but public diverges more often.