This error is the result of incompatibilities between the Qt library expected by SecAst, and the Qt library installed on your system (or possibly because you are missing the Qt library altogether). SecAst version 1.7.0 is built against Qt version 5.9.8, so that is the library version you should install (at this date).
There is often a gap between the Qt version we use for a software release, and what is available across all Linux distributions / repos. (Each distribution / repo makes a slightly different version available). This problem should resolve itself once the repos catch caught up. Note that even version 5.9.8 is many releases behind the most current Qt version, so we are staying well away from leading edge.
As of July 13 2020 the Qt library available from Ubuntu 18’s official repos is 5.9.5. If you are a customer with a SecAst maintenance agreement we can build a release for you using Qt library 5.9.5 (or whatever version you need) at no charge. If you are using the free edition you can either wait (for your repo to catch up), or install the Qt open source libraries from: http://www.qt.io/download-open-source as those will always offer the very latest libraries
