Microsoft is going to auto-update Windows 10 v1803 and older to Windows 10 May 2019 Update (v1903)

Starting 16th July 2019, Microsoft is initiating the installation of Windows 10 May 2019 Update to customers having Windows 10 version 1803 or older (Home or Pro). If you are one of them, you will start seeing the notification of Windows 10 May 2019 Update.