Over the past few years, Google has been updating our APIs with new versions across Drive and Calendar, as well as those used for managing Google Apps for Work domains. These new APIs offered developers several improvements over older versions of the API. With each of these introductions, we also announced the deprecation of a set of corresponding APIs.

As communicated* back in September, the deprecation period for these APIs is coming to an end. As of April 20, 2015, we will discontinue these deprecated APIs. Calls to these APIs and any features in your application that depend on them will not work after April 20th.

Discontinued API
Replacement API
No replacement available

When updating, Google also recommends that you use the opportunity to switch to OAuth2 for authorization. Older protocols, such as ClientLogin, AuthSub, and OpenID 2.0, have also been deprecated and are scheduled to shut down.

In the coming weeks, they’ll be contacting domain administrators whose applications are still using these deprecated APIs with an email reminder and guidance on specific migration paths.