'Extended support for Windows Embedded POSReady 2009 -- the last supported version of Windows based on Windows XP -- ended on April 9, 2019, marking the final end of the Windows NT 5.1 product line after 17 years, 7 months, and 16 days. Counting this edition, Windows XP is the longest-lived version of Windows ever -- a record which is unlikely to be beaten.

Despite the nominal end of support for Windows XP five years ago, the existence of POSReady 2009 allowed users to receive security updates on Windows XP Home and Professional SP3 through the use of a registry hack. Microsoft dissuaded users from doing this, stating that they "do not fully protect Windows XP customers," though no attempt was apparently made to prevent users from using this hack. With POSReady reaching the end of support, the flow of these security updates will likewise come to an end.'

-- source: https://tech.slashdot.org/story/19/04/10/0017208

Cheers, Peter