I have just received this message from GoogleDevelopersfirstname.lastname@example.org about the Google+ API I am using for a Web application:
On March 7, 2019, all Google+ APIs and Google+ Sign-in will be shut down completely. This will be a progressive shutdown, with API calls starting to intermittently fail as early as January 28, 2019, and OAuth requests for Google+ scopes starting to intermittently fail as early as February 15, 2019.
What do I need to do?
Please update your projects listed below by March 7, 2019 and ensure they are no longer using Google+ APIs, or requesting Google+ OAuth scopes. The data below shows which Google+ API methods your projects have recently called, as well as Google+ OAuth scopes it has requested.
It is not clear what is the replacement for this. The goal is to still allow users to authenticate in my Web application using their Google account.
Question: What shall I consider as replacement for Google+ APIs and OAuth?