For security reasons, you must disallow code uploads to production instances and require a client certificate for code uploads to staging instances. We mandated this configuration by April 1, 2020, but did not start proactive enforcement because of COVID-19. As of August 1, 2020, we will start proactive enforcement.
How: To check current access settings for code uploads, go to . The message under the Cartridges heading indicates whether code upload is allowed or disallowed on production instances and whether a client certificate is required on staging instances. To set access settings for code uploads, go to . After an administrator disallows code uploads to production instances or specifies that a client certificate is required for code uploads to staging instances, the option to revert the settings is no longer visible on the Access Restriction page. Only Salesforce Customer Support can revert the settings.