I have tried adding a Next Day service to the EVRi Corporate integration, but could not see it in the list of available services.
In order to add EVRi Next Day service, first you will need to go to Linnworks.net > Shipping > Integrations > EVRi Corporate > Services screen and add EVRi Standard 48Hr service and click on Add button.
After this step is completed, you will need to click on the Edit button after adding the service.
Enable the 'Next Day' option and then click on Save button to apply the changes.
You can give the Linnworks postal service a different name, so you will recognise it across the system to indicate that it's a 24Hr service.