We're aware of an issue with the Flarum 2.0 haptic feedback not working on iOS 26.5, this is due to Apple closing the software to the haptic implementation used by the web-haptics library (Apple does not support naitive haptic feedback from the web). Earlier iOS versions are not affected, nor is the Android platform - these continue to function as intended.
I've opened an issue to track this, but there is little we can do within Flarum to fix this right now. Putting this here as a PSA more than anything.
Of course, if you have an idea on what can be done to resolve this for iOS users, feel free to chime in!
flarum/framework4694