The error message indicates that the SaaS provider has deprecated a function that was previously called by the custom integration. The best action for the application owner to take is to update the custom integration to use a function that is supported in the current release. This is a direct solution to the problem and ensures the custom integration conforms to the updated SaaS provider's API. Reference: Based on the error message provided and standard practices for dealing with deprecated API calls in a SaaS environment.