Windows 7 users: You need SHA-2 support or no Windows updates after July 2019

Windows 7 and Windows Server 2008 users need to have SHA-2 code-signing installed by July 16, 2019, in order to continue to get Windows updates after that date. Microsoft issued that warning on February 15 via a Support article .

Windows operating system updates are dual-signed using both the SHA-1 and SHA-2 hash algorithms to prove authenticity. Bug going foward, due to "weaknesses" in SHA-1, Microsoft officials have said previously that Windows updates will be using the more secure SHA-2 algorithm exclusively. Customers running Windows 7 SP1, Windows Server 2008 R2 SP1 and Windows Server 2008 SP2 must have SHA-2 code-signing support installed by July 2019, Microsoft officials have said.

Microsoft has published a timeline for migrating these operating systems to SHA-2, with support for the algorithm coming in standalone updates. On March 12, Microsoft is planning a standalone update with SHA-2 code sign support for Windows 7 SP1 and Windows Server 2008 R2 SP1. It also will deliver to WSUS 3.0 SP2 the required support for delivering SHA-2 updates.

Microsoft will make available a standalone update with SHA-2 code sign support for Windows Server 2008 SP2 on April 9, 2019.

On June 18, Windows 10 updates -- 1709, 1803, 1809 and Server 2019 -- will have their signatures changed from dual-signed SHA-1/SHA-2 to SHA-2 only with no customer action required.

The full cut-over timetable is available on Microsoft's support page .

SHA-1, or Secure Hash Algorithm 1 , was introduced by the National Security Agency in 2002. It has been used in SSL certificates, encrypted communications and code revision-control systems. SHA-2 uses SHA-1's algorithm, but it uses different input and output sizes for far superior security. Microsoft began blocking sites signed with SHA-1 certificates in its Edge and IE browsers back in 2017.