Sarah Perez, reporting for TechCrunch:
The MLB.com At Bat and NHL iOS applications have been updated today to take advantage of one of the new, but still under-the-radar features available in the just-launched version of Apple’s mobile operating system, iOS 10.3: personalized home screen icons. That’s right — you now can replace either of these apps’ default icon with one featuring your favorite team’s logo instead.
The ability for developers to offer alternative icons was spotted earlier this year in the beta builds of iOS 10.3, but it wasn’t clear at the time how the technology would be put to use.
As Perez writes, apps like MLB At Bat are a perfect fit for this feature. I bet other leagues (the NFL, NBA) will make use of this API eventually. I've seen speculation on Twitter that Apple built this API at the request of MLB. It's a neat touch; I tweeted about it this morning.