To switch on clean and auto post of dispatches perform the following steps:
- Go to Setup ---> Account Settings
- Under 'Dispatch' switch on 'Allow Clean and Auto Post of Dispatches'

Turning this option on will do the following.
Xero Integration
When a dispatch is created from the Xero integration it will be assigned the oldest batch with inventory and the dispatch line will then be automatically posted.
Dispatch Screen
You will see two new options available in the dispatch screen:
- Clean Dispatches
- Allocate and Post Dispatches

Clean Dispatches
Selecting this option will remove/delete all dispatch headers that have no dispatch lines associated with them. This may sometimes happen if Xero creates a dispatch header but doesn't create any dispatch lines.
Allocate and Post Dispatches
This runs the same function that is run in the Xero integration to allocate the oldest batch to each dispatch line and then post the dispatch record. This action will be performed on all un-posted dispatches