Call Blocking (CallKit) not working on iOS 26 Public Beta

Call blocking using a third-party CallKit app is not longer working with the latest iOS 26 Public Beta (23A5297m).

We've tried several different Call Blocking apps (that used to work fine on iOS 18.5) and their call blocking functionality is not working anymore.

All calls pass through and the phone rings on those "blocked" numbers. We got several user complaints about our app that is not working on iOS 26 Public Beta.

We've filed 2 bug reports with Feedback Assistant:

  • FB19140680
  • FB19140594

Please fix this issue in the next Beta versions of iOS 26 to have a stable iOS 26 release in the future. Thank you in advance.

Answered by DTS Engineer in 852207022

I have also tested with a factory reset device (using the debugging profile) and still the call blocking didn't work. I have attached a sysdiagnose ZIP as well in the FB bug (sysdiagnose_2025.08.05_10-45-11+0300_iPhone-OS_iPhone_23A5297m.tar.gz)

Perfect, thank you. The set of logs taken with the debug profile were particularly helpful, and the team has found the issue, which was caused by an existing, subtle difference between how communicationd and callservicesd, which other changes in underlying infrastructure then exposed. I can't provide any specific timeline or scheduling, but the bug fix is straightforward and high priority.

__
Kevin Elliott
DTS Engineer, CoreOS/Hardware

I have also tested with a factory reset device (using the debugging profile) and still the call blocking didn't work. I have attached a sysdiagnose ZIP as well in the FB bug (sysdiagnose_2025.08.05_10-45-11+0300_iPhone-OS_iPhone_23A5297m.tar.gz)

Perfect, thank you. The set of logs taken with the debug profile were particularly helpful, and the team has found the issue, which was caused by an existing, subtle difference between how communicationd and callservicesd, which other changes in underlying infrastructure then exposed. I can't provide any specific timeline or scheduling, but the bug fix is straightforward and high priority.

__
Kevin Elliott
DTS Engineer, CoreOS/Hardware

That's great news!

Thank you for the thorough investigation and handling of the issue. I really appreciate the collaborative approach in getting to the root cause. I'll keep an eye on future releases and I'm happy to test this with a (possible) new beta release when the fix is implemented.

The issue persists in iOS 26 Beta 6 (Build 23A5318c). I have attached a new sysdiagnose collected from the latest build for your review in the FB bug.

I also tested on iOS 26 Beta 6 (Build 23A5318f), but blocked calls still pass through.

The issue persists in iOS 26 Beta 6 (Build 23A5318c).

As come quick follow up on this, yes, the issue is not fixed in beta 6. As some background context, there is a significant testing process before every beta is released, so it's not unusual for a bug to be completely "fixed" (meaning, all code changes have been submitted and are "in" that release) but miss the "next" beta release because that release is already locked and in testing.

I also tested on iOS 26 Beta 6 (Build 23A5318f), but blocked calls still pass through.

In a similar vein, the minor letter (c vs f) is primarily used to designate differences that are outside the actual code/build, like the distribution mechanism (in this case, the developer seed vs. the public beta). While it's possible there have been exceptions, I would not expect there to be ANY substantial behavioral difference* between those two build.

*The obvious exception would be issues caused by differences in the install or configuration pipeline, which is why we don't use exactly the same build version for both cases.

__
Kevin Elliott
DTS Engineer, CoreOS/Hardware

Ok, thanks for the clarification. I’ll be waiting for the fix in the next beta (or stable) release version.

I have tested with iOS 26 Beta 7 (23A5326a) and the bug is fixed.

Calls are now blocked when a blocking rule is set with addBlockingEntryWithNextSequentialPhoneNumber from CallKit API.

I have closed the FB issue. Thanks for fixing that.

Call Blocking (CallKit) not working on iOS 26 Public Beta
 
 
Q