The new iPhone 17 doesn’t work with Apple Watch 4

After switching to the new iPhone 17, my Apple Watch Series 4 (10.6.1 21U580) stopped working properly. Here’s what happens: if I set them up as new, they connect and work fine for a while. I can install all apps, receive notifications, and successfully add Apple Pay cards. However, after leaving them overnight, they can no longer connect to the phone. Restarting both devices doesn’t help — the only solution is to reset the watch and pair it again, and then it works for up to one day at most.

This issue occurs on the iPhone 17 running iOS 26.0, 26.0.1.

I also have an iPhone 13 Pro running iOS 18.6.2, and with that device, the same Apple Watch works perfectly — the connection is stable, and everything functions as expected.

I’ve been waiting since I bought the iPhone 17 for this issue to be fixed, but the problem has persisted since September 19, when I purchased the device. Every available iOS version for the iPhone 17 has the same problem.