Windows 10 Mobile is not getting any more new features or major improvements. Microsoft is still supposed to release security updates each month. The restrictive Windows 10 Mobile platform offers much better security than open-source Android. Today the platform is receiving a new cumulative update with security fixes.
If your Windows Phone is running on Windows 10 Fall Creators Update you will be getting 15254.538, up from 15254.530. If your Windows Phone is on Creators Update, you will receive Build 15063.1390 and it comes with unknown changes.
In other news, Microsoft ended support for Windows 10 Mobile Anniversary Update and you will no longer receive any security patches if your phone is running this version of Windows 10.
Windows 10 Mobile has just 1 year of support left but the Windows Store and the first-party apps are likely to function beyond 2019.