The Most recent security intelligence virus definitions update for defender is version 27, 2025. The most recent full platform engine update was from Engine version 1.1.2 platform version 9008. According to official documentation for Microsoft Defender for Endpoint, updates released October 2025 platform 4.18.25100.9008 engine 1.1.25100.9002 fixed issues like stability of the network inspection service and improved time of the antimalware service.
Even though mainstream support for Windows 10 has ended, Defender’s virus definition updates will continue until at least 2028, so devices running Windows 10 remain protected at the malware definition level. That said, other Windows system updates and feature updates may no longer come, so using a fully supported OS version is still recommended for best security.
Even though mainstream support for Windows 10 has ended, Defender virus definition updates will continue until at least 2028, so devices running Windows 10 remain protected at the malware definition level. That said, other Windows system updates and feature updates may no longer come, so using a fully supported OS version is still recommended for best security. Some users on Windows 11 version 24H2 have reported problems their Defender virus definition last update date hasn’t changed since 19 November 2025, even though Microsoft is releasing definitions. Because of that, you might want to check manually in Settings Windows Security Virus and threat protection Protection updates to ensure your definitions are truly up to date.
