Hello, most black screen issues have been reported as resolved in previous updates, so this may be a more specific case.
Please contact support@flufflop.com with your OS type and version. If the app can still be launched, you can generate a report from Settings > About > Generate Report at the bottom of the page and attach it, which helps the most.
If possible, a short screen recording showing when and how the black screen occurs would also be very helpful for identifying the cause.