When users access third-party services through our Google, Facebook or Twitter accounts, among others, behind this possibility is the OAuth 2.0 protocol, which is the one currently used, since it is safer and more secure. easy to implement for the developers of applications and web services.
In this sense, Google is addressing developers in recent days to urge them to migrate their applications and services that connect with Google to OAuth 2.0 service accounts with delegation of the entire domain in case they still work with OAuth. 1.0 (2LO), since otherwise, as of October 20 of this year, these applications and services will experience problems until they migrate to a supported protocol.
Google specifies that it was last April 20, 2015 when it removed support for OAuth 1.0 (3LO), which is the version that urged end users to give their explicit consent to authorize access.
The version that will no longer have support this coming October is the OAuth version 1.0 (2LO), used in business authorization scenarios, not involving end users, allowing, among other aspects, to apply access control policies within the organization itself .
In this way, Google gives developers enough time frame for developers to migrate their applications to the current authorization protocol, in fact assuming the final phase to definitively abandon the use of OAuth 1.0. In its whole.