Standard extended support ended January 14, 2020. Paid Extended Security Updates (ESU) for on-premises servers ended in early 2023, though some Azure-hosted workloads received support until January 2024 .
If you see Build 6003 on your servers, pat yourself on the back for keeping them as secure as possible – but immediately plan your move to a supported OS. Build 6003 is the end of the road, not the beginning of a new one. windows server 2008 build 6003 upd
Running build 6003 does not make Windows Server 2008 secure or supported. It merely reflects that a now‑expired ESU patch was applied. After January 2023, no new security fixes are available for any build of Windows Server 2008. Standard extended support ended January 14, 2020
Build number changing to 6003 in Windows Server 2008 - Microsoft Support Build 6003 is the end of the road,