Update on ERROR ITMS-90502: "Invalid Bundle. Apps that only contain the arm64 slice must also have 'arm64' in the list of UIRequiredDeviceCapabilities in Info.plist."
This looks to be an issue with armv7 / armv7s architecture flags hanging around after a project has been transitioned to arm64 only.
UIRequiredDeviceCapabilities flag for arm64 previously was enough to block 32bit installs, but Apple must have silently changed their criteria yesterday to enforce that explicitly across all proj files within a bundle. Our main project had fully transitioned to 64bit, but an internal SDK proj and our Pods proj still had armv7/armv7s flags.
Adding this to the podfile was enough to fix the issue:
post_install do |installer| installer.pods_project.build_configurations.each do |config|