If you use the OnStar RemoteLink app on your Windows phone, it looks like your time with the app is pretty limited. OnStar has begun sending letters to customers, alerting them to the fact that support for the RemoteLink app will be discontinued due to a "system change" later this year.

OnStar is killing its RemoteLink app for Windows phones

From the letter:

In order to continue providing the best mobile app experience, we will be implementing a system change to the OnStar RemoteLink mobile app later this year. This will discontinue RemoteLink mobile app support for your BlackBerry or Windows smartphone. To continue using the mobile application, it will require a Google Android or Apple iOS device meeting the minimum operating system requirements. This update will also impact the myChevrolet, myBuick, myCadillac or myGMC mobile apps. More information can be found at www.onstar.com/mobileapp.

The OnStar RemoteLink app provides quite a few handy features for subscribers, including remote start, remote door locking and unlocking, vehicle status and much more. The app, however, has been rarely updated on Windows phone, with the last notable update bringing a redesign in 2015. Given that lack of continued support and the current status of the platform, it's not unsurprising to see OnStar dropping support for the app.

There's no clear date provided other than "later this year." Still, if you heavily rely on the RemoteLink app, you'll want to figure out an alternative relatively soon.

Thanks to macros_1, Robert, DW, and Jared for the tips!