As announced last fall, we’ve been disabling SHA-1 for increasing numbers of Firefox users since the release of Firefox 51 using a gradual phase-in technique. Tomorrow [Feb 24th], this deprecation policy will reach all Firefox users. It is enabled by default in Firefox 52.
To be fair (although I've been commenting angrily about git's continued use of SHA-1 elsewhere) it's a lot easier for a browser to change hash algorithms than for git.
* The end of SHA-1 on the Public Web
https://blog.mozilla.org/security/2017/02/23/the-end-of-sha-...
As announced last fall, we’ve been disabling SHA-1 for increasing numbers of Firefox users since the release of Firefox 51 using a gradual phase-in technique. Tomorrow [Feb 24th], this deprecation policy will reach all Firefox users. It is enabled by default in Firefox 52.