If you're still running Windows 10 version 1511, also known as the Windows 10 November Update, you may want to upgrade now.
This version will no longer receive security updates after 10 October, Microsoft said in a support note urging users to install the latest version Windows 10, which is currently the Creators Update from April.
The end of support for Windows 10 version 1511 comes a week ahead of the planned launch of the Windows 10 Fall Creators Update or version 1709.
The remaining supported versions of Windows 10 include the Anniversary Update (1607) and the Creators Update (1703). Tentative dates that these versions will no longer receive security patches are March 2018 and September 2018, respectively.
Even though support for version 1511 officially ends tomorrow, Microsoft has been notifying and nudging users on this version as well as the original version 1507 to upgrade to the Creators Update. Support for version 1507 ended in May.
As Microsoft explained earlier this year, it was prompting users on an older version of Windows 10 to review their privacy settings as part of a process to initiate an update to the Creators Update. Users could still control when the update is installed, but could only postpone the privacy review five times.
The end of support for version 1511 affects Windows 10 Home, Windows 10 Pro, Windows 10 Education, and Windows 10 Enterprise.
Despite continuing to support older versions of Windows 10, Microsoft is encouraging users to install the latest version on the grounds that it has added new security features that weren't included in prior versions.
"Since version 1511 was released in November 2015, Microsoft has released additional feature updates that build upon each other, delivering the newest features and more comprehensive security.
"Windows 10 was designed as a service, whereby feature updates are required a couple times a year," it notes.