Windows 10 Mobile Creators Update (version 1703) will stop supporting today, which means includingMicrosoftWP like Lumia 640 and Lumia 640 XLMobile phoneMonthly cumulative updates will no longer be available. If you have a device running Version 1703 on hand, then Build 15063.1868 is the last version update.
With the Windows 10 Mobile creator update coming to the end of life, only a few devices running the Version 1709, such as the Lumia 950 and the Lumia 650, are now available for updates. However, it is worth noting that Version 1709 will also be discontinued in December 2019. Any WP phone will not receive monthly updates until 2020.