Apple released for sale a critical update to our iOS app 7 days ago today. Since then, the vast majority of our App Store installs and updates have been the new version, but a small portion of the updates (less than 1%) are the old version, as reported by iTunes Connect. This has continued day after day, and is concerning because some users are getting a crash-prone version of our app.
How are users still updating to the old version 7 days after we released an update? Is there any way to prevent this?
(The targeted iOS versions have not changed; the app is and has only ever been available on the US store.)