This month is the beginning of when this should start to occur, but you should see more of these over the next couple years. Longer running certificates will be hit first, and then as we get closer, other certificates will receive the warnings. IE, Firefox, Safari and other browsers may start to issue warnings leading up to 2017.
So, if you have been impacted by this, and you’re a site owner, you should contact your certificate authority and ask for them to reissue your certificate using SHA-2 instead.
If you are a web user and you see this warning, you can contact the site owner to make sure that they are aware of the warning. The site is no less secure today than it was last month, but Google is starting to bring awareness to the less secure SHA-1 signed certificates.