OAuth 2 LinkedIn service
From 1 May 2019, LinkedIn no longer support their v1 API, which could previously be configured as an OAuth 2 authentication method in Moodle. According to LinkedIn's v2 API migration documentation, the new API replaces the old basic user information endpoint with a 'lite' endpoint, which does not include a user's email address (which must be retrieved from a separate endpoint).
Since email address is a required field in Moodle, and our OAuth 2 implementation currently requires all user information to be retrieved from a single endpoint, the LinkedIn v2 API currently appears to be incompatible with Moodle's "Custom OAuth 2 Service" feature.
We are continuing to investigate a workaround for the new API, and will update this documentation further when a solution can be found. In the meantime, if you have any information that may assist with this, please contribute to Tracker issue MDL-65637.