We removed the legacy GitHub OAuth integration from GitHub.
This integration was discontinued from active use in 2019, however remained configured for many repositories.
We do not expect any customer impact, however you may notice entries in your GitHub audit trail for the integration being removed from older projects.
In the unlikely case you are impacted, then the two most likely scenarios are described below.
If you experience a failure to trigger builds:
Go to GitHub and ensure the app is correctly configured - https://github.com/apps/codeship/installations/new
If you find your CodeShip builds are not able to checkout code:
Then follow the instructions for resetting the SSH key - https://documentation.codeship.com/general/projects/project-ssh-key