One thing to keep in mind if you're updating an older app that had armv7 and x86, and replacing it with a new version that's armv7 and armv8: A lot (or most?) of x86 devices are able to run the armv7 version if there isn't an x86 version in the release, but you'll have to make sure that the version number you're using for your new armv7 version is higher than the version number for your old x86 version.
If you kept the version numbers close originally (armv7 = 1.0.0, x86 = 1.0.1), then you can just keep incrementing and shouldn't have a problem. But if you spaced them out previously, for example if your armv7 was 1.0.0 and x86 was 2.0.0, make sure your NEW armv7 is at least 2.0.1 so any devices that previously had the x86 version can get the update. If you just set your new armv7 to 1.0.1 in this case, armv7 devices could get the update, but x86 devices wouldn't be able to get the update because the version number is lower than what they had previously.