Tacx has adopted the ANT+ FE-C standard for their Smart line of Trainers (the Bushido Smart and the Vortex Smart, along with their Tour de France versions). This means Zwift can now control resistance on these trainers and read their wattage.
Before beginning the update process, turn on Bluetooth in your settings.
Open the Tacx Utility App. Your trainer will appear on the main screen. Select it.
The Utility app will detect your current firmware version and give you the option to upgrade to version 3.1.7 or newer. Tap "Upload firmware" to begin the process.
After the upload completes, a completion message will appear. Unplug the power cord as directed, and then plug it back in.
The update is complete! To confirm that the update completed, click on your trainer from the app again, and verify that the firmware version number of your trainer matches the version number of the update.
Enjoy the climbs and descents!