Subcontractor's shifts need to be published individually by each subcontractor instead of using the red Publish button as you would for a regular staff member.
1. Go to the Schedule page and hover over the subcontractor's name.
2. Click on the three vertical dots that appear and choose Send Rota. This action will publish all the assigned shifts that are currently visible in the calendar for that subcontractor. It will also at the same time send the rota to the subcontractor.
If you wish to publish an individual shift for a subcontractor, simply right click on the shift itself and choose Publish. It will then give you the option to send a notification about it to the subcontractor should you wish to do so.