Apple Newsroom: An Update on Blood Oxygen for Apple Watch in the U.S.

There will be no impact to Apple Watch units previously purchased that include the original Blood Oxygen feature, nor to Apple Watch units purchased outside of the U.S.

This weird saga continues, and it's good that Apple's been able to bring it back, but this part is annoying:

Blood Oxygen app on Apple Watch will be measured and calculated on the paired iPhone, and results can be viewed in the Respiratory section of the Health app.

Basically, you can once again do the measurement on the watch itself, but you can't see the result on your watch, you need to open the Health app on your iPhone to see it. Definitely annoying, but the good news is that if your watch was purchased before Apple had to remove this feature, yours still works the same way it always has. I just ran a test on my Apple Watch Ultra 2 and saw the 98% displayed on the screen, so you're not losing functionality you already had.