We recommend staying on macOS 10.13.3 or upgrading to 10.14.2 +
This issue is completely resolved in 10.14.2 and later
Installing macOS release Version 10.13.4 will cause Duet Display to not function at full performance after the OS upgrade – these features continue to work as expected in 10.13.3.
We would strongly recommend staying on 10.3.3 or upgrading to 10.14.2, which fixes the issue. Please e-mail us at firstname.lastname@example.org if you have any questions.
Thank you for using Duet!