I didn't make any changes to the build process between versions and I didn't update Ren'Py, so I'm unsure as to what might be causing that. I'll do a little research, but iOS is not a supported environment.
I'm looking at the Spark page on the App Store and it looks like there's a way to select a Ren'Py version to improve stability. TNoM is built on 8.3.4, so perhaps selecting that will help.
Out of curiosity, which version do you use with it: Android, Win/Linux, or Mac?