Phased vs. Regular Update Adoption Rates
For several years now Apple has offered Phased Rollouts for app updates in the App Store. This lets you slow down the adoption of a new update to your users by limiting the number of users who are offered it as an automatic update each day.
[…]
I was very pleased to see the system work so well. The rollout was slow and measured. It let me find a few things I needed to fix before the update got out to all my users.
Also remarkable to me is how quickly the ‘immediate rollout’ really is. With around 80% adoption in just a couple of days.
Of course, phased releases are not supported by the Mac App Store.
Update (2019-03-20): Apple:
You can now release an update to your macOS app in stages by enabling Phased Release for Automatic Updates in App Store Connect.