Safe OS Dynamic Updates
Recovery environment updates, tracked separately from Windows cumulative and Setup Dynamic Updates.
SafeOS updates service the Windows recovery environment (WinRE) used during recovery and feature updates. They can include security fixes and reliability improvements. A catalog classification of Critical Updates is not a CVE severity rating.
Installation channels, prerequisites, replacement information and the need to update installation media vary by KB. Always check the Microsoft deployment guidance and the relevant support article. This listing does not assess whether a device's WinRE is patched.
Package history
714 packages · 262 KB articles · Last successful refresh: . Automatic discovery every 6 hours. Microsoft Update Catalog source
714 matching packages. Each row is a catalog package; the same KB can apply to multiple versions and architectures.
Release date and package build come from the KB article when available. Catalog revised is Microsoft's catalog revision date, not the original release date. Missing article details are explicitly marked and retried automatically.
| Product / version | Architecture | KB / details | Release date | Catalog revised | Package build | Catalog |
|---|---|---|---|---|---|---|
| Windows 11 26H1 | arm64 |
KB5124013
Details2026-09 Safe OS Dynamic Update for Windows 11, version 26H1 for arm64-based Systems (KB5124013) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 157.4 MB. |
2026-09-22 | 2026-09-22 | 28000.3086 |
Package / download |
| Windows 11 26H1 | x64 |
KB5124013
Details2026-09 Safe OS Dynamic Update for Windows 11, version 26H1 for x64-based Systems (KB5124013) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 136.3 MB. |
2026-09-22 | 2026-09-22 | 28000.3086 |
Package / download |
| Windows 11 24H2 | arm64 |
KB5125758
Details2026-09 Safe OS Dynamic Update for Windows 11, version 24H2 for arm64-based Systems (KB5125758) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 205.5 MB. |
2026-09-22 | 2026-09-22 | 26100.9545 |
Package / download |
| Windows 11 24H2 | x64 |
KB5125758
Details2026-09 Safe OS Dynamic Update for Windows 11, version 24H2 for x64-based Systems (KB5125758) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 174.4 MB. |
2026-09-22 | 2026-09-22 | 26100.9545 |
Package / download |
| Windows 11 25H2 | arm64 |
KB5125758
Details2026-09 Safe OS Dynamic Update for Windows 11, version 25H2 for arm64-based Systems (KB5125758) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 205.5 MB. |
2026-09-22 | 2026-09-22 | 26100.9545 |
Package / download |
| Windows 11 25H2 | x64 |
KB5125758
Details2026-09 Safe OS Dynamic Update for Windows 11, version 25H2 for x64-based Systems (KB5125758) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 174.4 MB. |
2026-09-22 | 2026-09-22 | 26100.9545 |
Package / download |
| Windows 11 26H2 | arm64 |
KB5125758
Details2026-09 Safe OS Dynamic Update for Windows 11, version 26H2 for arm64-based Systems (KB5125758) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 205.5 MB. |
2026-09-22 | 2026-09-29 | 26100.9545 |
Package / download |
| Windows 11 26H2 | x64 |
KB5125758
Details2026-09 Safe OS Dynamic Update for Windows 11, version 26H2 for x64-based Systems (KB5125758) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 174.4 MB. |
2026-09-22 | 2026-09-29 | 26100.9545 |
Package / download |
| Windows 11 26H1 | arm64 |
KB5129255
Details2026-09 Safe OS Dynamic Update for Windows 11, version 26H1 for arm64-based Systems (KB5129255) This out-of-band update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 152.7 MB. |
2026-09-14 | 2026-09-14 | 28000.2957 |
Package / download |
| Windows 11 26H1 | x64 |
KB5129255
Details2026-09 Safe OS Dynamic Update for Windows 11, version 26H1 for x64-based Systems (KB5129255) This out-of-band update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 131.2 MB. |
2026-09-14 | 2026-09-14 | 28000.2957 |
Package / download |
| Microsoft server operating system 24H2 | x64 |
KB5122883
Details2026-09 Safe OS Dynamic Update for Microsoft server operating system version 24H2 for x64-based Systems (KB5122883) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 144.1 MB. |
2026-09-08 | 2026-09-08 | 26100.33435 |
Package / download |
| Windows 10 1607 | x64 |
KB5122885
Details2026-09 Dynamic Update for Windows 10 Version 1607 for x64-based Systems (KB5122885) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 187.4 MB. |
2026-09-08 | 2026-09-08 | 14393.9507 |
Package / download |
| Windows 10 1607 | x86 |
KB5122885
Details2026-09 Dynamic Update for Windows 10 Version 1607 for x86-based Systems (KB5122885) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 153.2 MB. |
2026-09-08 | 2026-09-08 | 14393.9507 |
Package / download |
| Windows 10 1809 | x64 |
KB5122886
Details2026-09 Dynamic Update for Windows 10 Version 1809 for x64-based Systems (KB5122886) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 153.2 MB. |
2026-09-08 | 2026-09-08 | 17763.924 |
Package / download |
| Windows 10 1809 | x86 |
KB5122886
Details2026-09 Dynamic Update for Windows 10 Version 1809 for x86-based Systems (KB5122886) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 121.5 MB. |
2026-09-08 | 2026-09-08 | 17763.924 |
Package / download |
| Windows 10 21H2 | arm64 |
KB5122887
Details2026-09 Dynamic Update for Windows 10 Version 21H2 for ARM64-based Systems (KB5122887) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 187.7 MB. |
2026-09-08 | 2026-09-08 | 19041.7722 |
Package / download |
| Windows 10 21H2 | x64 |
KB5122887
Details2026-09 Dynamic Update for Windows 10 Version 21H2 for x64-based Systems (KB5122887) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 146.0 MB. |
2026-09-08 | 2026-09-08 | 19041.7722 |
Package / download |
| Windows 10 21H2 | x86 |
KB5122887
Details2026-09 Dynamic Update for Windows 10 Version 21H2 for x86-based Systems (KB5122887) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 120.9 MB. |
2026-09-08 | 2026-09-08 | 19041.7722 |
Package / download |
| Windows 11 23H2 | arm64 |
KB5122888
Details2026-09 Safe OS Dynamic Update for Windows 11, version 23H2 for arm64-based Systems (KB5122888) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 184.5 MB. |
2026-09-08 | 2026-09-08 | 22621.7581 |
Package / download |
| Windows 11 23H2 | x64 |
KB5122888
Details2026-09 Safe OS Dynamic Update for Windows 11, version 23H2 for x64-based Systems (KB5122888) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 152.7 MB. |
2026-09-08 | 2026-09-08 | 22621.7581 |
Package / download |
| Microsoft server operating system 21H2 | x64 |
KB5122889
Details2026-09 Dynamic Update for Microsoft server operating system version 21H2 for x64-based Systems (KB5122889) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 141.5 MB. |
2026-09-08 | 2026-09-08 | 20348.562 |
Package / download |
| Windows 11 26H1 | arm64 |
KB5124011
Details2026-09 Safe OS Dynamic Update for Windows 11, version 26H1 for arm64-based Systems (KB5124011) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 153.1 MB. |
2026-09-08 | 2026-09-08 | 28000.2949 |
Package / download |
| Windows 11 26H1 | x64 |
KB5124011
Details2026-09 Safe OS Dynamic Update for Windows 11, version 26H1 for x64-based Systems (KB5124011) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 130.8 MB. |
2026-09-08 | 2026-09-08 | 28000.2949 |
Package / download |
| Windows 11 24H2 | arm64 |
KB5124015
Details2026-09 Safe OS Dynamic Update for Windows 11, version 24H2 for arm64-based Systems (KB5124015) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 191.8 MB. |
2026-09-08 | 2026-09-08 | 26100.9444 |
Package / download |
| Windows 11 24H2 | x64 |
KB5124015
Details2026-09 Safe OS Dynamic Update for Windows 11, version 24H2 for x64-based Systems (KB5124015) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 162.9 MB. |
2026-09-08 | 2026-09-08 | 26100.9444 |
Package / download |
| Windows 11 25H2 | arm64 |
KB5124015
Details2026-09 Safe OS Dynamic Update for Windows 11, version 25H2 for arm64-based Systems (KB5124015) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 191.8 MB. |
2026-09-08 | 2026-09-08 | 26100.9444 |
Package / download |
| Windows 11 25H2 | x64 |
KB5124015
Details2026-09 Safe OS Dynamic Update for Windows 11, version 25H2 for x64-based Systems (KB5124015) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 162.9 MB. |
2026-09-08 | 2026-09-08 | 26100.9444 |
Package / download |
| Windows 11 26H2 | arm64 |
KB5124015
Details2026-09 Safe OS Dynamic Update for Windows 11, version 26H2 for arm64-based Systems (KB5124015) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 191.8 MB. |
2026-09-08 | 2026-09-29 | 26100.9444 |
Package / download |
| Windows 11 26H2 | x64 |
KB5124015
Details2026-09 Safe OS Dynamic Update for Windows 11, version 26H2 for x64-based Systems (KB5124015) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 162.9 MB. |
2026-09-08 | 2026-09-29 | 26100.9444 |
Package / download |
| Windows 11 26H1 | arm64 |
KB5121001
Details2026-08 Safe OS Dynamic Update for Windows 11, version 26H1 for arm64-based Systems (KB5121001) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 146.0 MB. |
2026-08-27 | 2026-08-27 | Not available |
Package / download |
| Windows 11 26H1 | x64 |
KB5121001
Details2026-08 Safe OS Dynamic Update for Windows 11, version 26H1 for x64-based Systems (KB5121001) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 126.9 MB. |
2026-08-27 | 2026-08-27 | Not available |
Package / download |
| Microsoft server operating system 24H2 | x64 |
KB5120244
Details2026-08 Safe OS Dynamic Update for Microsoft server operating system version 24H2 for x64-based Systems (KB5120244) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 150.4 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 10 1607 | x64 |
KB5120246
Details2026-08 Dynamic Update for Windows 10 Version 1607 for x64-based Systems (KB5120246) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 170.5 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 10 1607 | x86 |
KB5120246
Details2026-08 Dynamic Update for Windows 10 Version 1607 for x86-based Systems (KB5120246) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 143.0 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 10 1809 | x64 |
KB5120247
Details2026-08 Dynamic Update for Windows 10 Version 1809 for x64-based Systems (KB5120247) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 150.3 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 10 1809 | x86 |
KB5120247
Details2026-08 Dynamic Update for Windows 10 Version 1809 for x86-based Systems (KB5120247) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 122.9 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 10 21H2 | arm64 |
KB5120248
Details2026-08 Dynamic Update for Windows 10 Version 21H2 for ARM64-based Systems (KB5120248) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 187.2 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 10 21H2 | x64 |
KB5120248
Details2026-08 Dynamic Update for Windows 10 Version 21H2 for x64-based Systems (KB5120248) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 144.4 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 10 21H2 | x86 |
KB5120248
Details2026-08 Dynamic Update for Windows 10 Version 21H2 for x86-based Systems (KB5120248) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 122.2 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 11 23H2 | arm64 |
KB5120250
Details2026-08 Safe OS Dynamic Update for Windows 11, version 23H2 for arm64-based Systems (KB5120250) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 193.5 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 11 23H2 | x64 |
KB5120250
Details2026-08 Safe OS Dynamic Update for Windows 11, version 23H2 for x64-based Systems (KB5120250) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 166.4 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Microsoft server operating system 21H2 | x64 |
KB5120251
Details2026-08 Dynamic Update for Microsoft server operating system version 21H2 for x64-based Systems (KB5120251) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 149.3 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 11 26H1 | arm64 |
KB5120999
Details2026-08 Safe OS Dynamic Update for Windows 11, version 26H1 for arm64-based Systems (KB5120999) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 148.0 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 11 26H1 | x64 |
KB5120999
Details2026-08 Safe OS Dynamic Update for Windows 11, version 26H1 for x64-based Systems (KB5120999) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 129.9 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 11 24H2 | arm64 |
KB5121002
Details2026-08 Safe OS Dynamic Update for Windows 11, version 24H2 for arm64-based Systems (KB5121002) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 187.0 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 11 24H2 | x64 |
KB5121002
Details2026-08 Safe OS Dynamic Update for Windows 11, version 24H2 for x64-based Systems (KB5121002) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 164.7 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 11 25H2 | arm64 |
KB5121002
Details2026-08 Safe OS Dynamic Update for Windows 11, version 25H2 for arm64-based Systems (KB5121002) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 187.0 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 11 25H2 | x64 |
KB5121002
Details2026-08 Safe OS Dynamic Update for Windows 11, version 25H2 for x64-based Systems (KB5121002) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 164.7 MB. |
2026-08-11 | 2026-08-11 | Not available |
Package / download |
| Windows 11 26H1 | arm64 |
KB5101718
Details2026-07 Safe OS Dynamic Update for Windows 11, version 26H1 for arm64-based Systems (KB5101718) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 147.5 MB. |
2026-07-28 | 2026-07-28 | Not available |
Package / download |
| Windows 11 26H1 | x64 |
KB5101718
Details2026-07 Safe OS Dynamic Update for Windows 11, version 26H1 for x64-based Systems (KB5101718) This update makes improvements to the Windows recovery environment (WinRE). Classification: Critical Updates. Size: 128.4 MB. |
2026-07-28 | 2026-07-28 | Not available |
Package / download |
Programmatic access: GET /api/WindowsVersions/safeos. See API access and authentication.