https://www.bleepingcomputer.com/news/microsoft/microsoft-pulls-windows-10-your-phone-release-and-sets-it-insider-only-again/

Earlier today there were reports of the Windows 10 Your Phone app being released and working with Windows 10 Build 1803. Unfortunately, it seems things were not working so well and Microsoft has decided to pull its release so it does not work with Windows 10 build 1803 and keep it only with Windows Insiders for the time being.

According to WindowsObserver, over the past 24 hours, Microsoft released the Your Phone app to Windows 10 users running build 1803, otherwise known as the April 2018 update. Prior to this, the Windows 10 app was only available to users running Windows Insider builds.