As I'm sure many readers are aware, Google+ is shutting down. This
affects Yesod's authentication
system. In particular,
any users of the
Yesod.Auth.GoogleEmail2 module will need to
Fortunately for all of us, Patrick Brisbin has written both the code for using Google Sign-in, but has also put together a great migration blog post. If you're affected, please check that out for a relatively painless migration.
As you may be able to tell from the
GoogleEmail2 module, this isn't
the first time we've had to migrate between Google authentication
APIs. Hopefully this one will stick.