09-20-2019, 07:59 PM
I hadn't been able to find any info on what version of iTunes support iOS 13, and more specifically, if the special iTunes 12.6.5 that still has the App store would work. So I did some experimenting.
https://support.apple.com/en-us/HT208079
All testing was done on Mac OS 10.12.6 (Sierra), and with an iPhone SE that was running iOS 12.4.1
Bottom line, it sort of works except it will not do anything that involves an iOS 13 firmware .ipsw file, it complains about the format of the file, so you can't update to iOS 13 through iTunes 12.6.5, and cannot restore the firmware, even using DFU mode with an iOS 13 firmware file. You can restore/downgrade an iOS 13 iPhone SE to 12.4.1 using the normal firmware restore process, or in DFU mode.
One thing about the iTunes 12.6.5 installer is that it can downgrade a newer iTunes (like 12.8.2), on Sierra, you can install 12.8.2, do any iOS 13 firmware activities needed, and then downgrade to 12.6.5.
And iTunes 12.8.2 will successfully install iOS 13 on an iPhone SE from Sierra. Alternatively, without even needing iTunes 12.8.2, one could upgrade the iPhone from 12.4.1 to 13.0 directly from the phone, and then just continue to use it with iTunes 12.6.5, and easily alternate between 12.6.5 and 12.8.2 as needed
There is a one-time message that comes up on Sierra the first time an iOS 13 iPhone SE is plugged in, saying that it needs to update device support for the phone, and doing that then allows either iTunes to work with it.
And as long as Apple continues to sign iOS 12.4.1 you can alternate between it and 13.0 if you want to test things out.
https://support.apple.com/en-us/HT208079
All testing was done on Mac OS 10.12.6 (Sierra), and with an iPhone SE that was running iOS 12.4.1
Bottom line, it sort of works except it will not do anything that involves an iOS 13 firmware .ipsw file, it complains about the format of the file, so you can't update to iOS 13 through iTunes 12.6.5, and cannot restore the firmware, even using DFU mode with an iOS 13 firmware file. You can restore/downgrade an iOS 13 iPhone SE to 12.4.1 using the normal firmware restore process, or in DFU mode.
One thing about the iTunes 12.6.5 installer is that it can downgrade a newer iTunes (like 12.8.2), on Sierra, you can install 12.8.2, do any iOS 13 firmware activities needed, and then downgrade to 12.6.5.
And iTunes 12.8.2 will successfully install iOS 13 on an iPhone SE from Sierra. Alternatively, without even needing iTunes 12.8.2, one could upgrade the iPhone from 12.4.1 to 13.0 directly from the phone, and then just continue to use it with iTunes 12.6.5, and easily alternate between 12.6.5 and 12.8.2 as needed
There is a one-time message that comes up on Sierra the first time an iOS 13 iPhone SE is plugged in, saying that it needs to update device support for the phone, and doing that then allows either iTunes to work with it.
And as long as Apple continues to sign iOS 12.4.1 you can alternate between it and 13.0 if you want to test things out.