When external routing is enabled, use the newest version (40.0) of Salesforce standard APIs and streaming APIs to connect Salesforce with an external routing implementation in your routing configuration. Then, create queues that use either Omni-Channel routing or your external routing implementation. But keep in mind, you can’t assign agents to queues of both types—they must either handle work from Omni-Channel routing or external routing. This change applies to Salesforce Classic only.
Multiple routing options, one console. Integrate an external routing implementation with your current Omni-Channel implementation to make routing in Salesforce even better.
Contact Salesforce to enable external routing with Omni-Channel.