Do you know that Microsoft Stop supporting Windows 8 Apps from July 2019? Yes, It is happening now. In a recent blog post by Windows Officials the company clarifies they stop accepting new apps for Windows phone version 8.X. Moreover, they also stop giving the app updates to Windows Phone version 8.x and its earlier devices. In fact, they also release the date from when they stop distributing app updates for all Windows 8/8.1 devices (that includes your laptops, PC or Tabs etc).
The last date they give to submit an app for Windows 8.x and earlier devices is October 31, 2018. After this date, I recommend you to don’t make and submit an app for Windows 8.x or earlier devices, because you can’t do so. For developers who already post an app for Windows 8.x and earlier devices on Microsoft store, they can present app updates until July 1, 2019.
In this blog post officials also present the last to distribute app updates in all Windows 8/8.1 devices, which is July 1, 2023. Microsoft officials, however, clear that one can post updates to the apps for Windows 10.
For developers who have posted there apps in Microsoft store, officials give them a guide on how to port their existing app for Windows 10. If you are a developer you can read it from here.