Thank you for your reply. Since before the bundle-identifier we declared in the download-manifest file of the older app version doesn't keep the same as the actual IPA package. Now we modified the bundle-identifier in the download-manifest file to be consistent with the app. We found that most iPhones can upgrade successfully, but only a few iPhones failed to upgrade. The download request of the new IPA is receiving the data, and the installation will be terminated immediately by the system as the logs show. I compare the install log of success and failed log. And I couldn't understand why the iOS system says the user canceled the installation. And why only some iPhones met the issue. It's very strange and confusing to me. Recently I have spent much time on this issue and need some help. I want to know about the detailed progress of the installation. _LSUnregisterBundle(<private>) returned 1 for placeholder only // Does this log matters?

sysdiagnose/MobileInstallation error log: Sat Jan 29 15:27:56 2022 [3738] <err> (0x16fa3f000) -[MIExecutableBundle updateMCMWithCodeSigningInfoAsAdvanceCopy:withError:]: Not pushing signing info to MCM because state was 0

We don't understand why only iOS 15.4 wait for the lock timeout.

Not only the app developed by us have the issue, also some other developer's apps have similar behavior, I have opened up a DTS and emailed to you.