PS6 is a completely new application with enhanced structure rather than simply a new release of PicoScope.
PS6 was designed primarily for our newer USB oscilloscopes, with an emphasis on performance rather than backward compatibility with legacy products.
PS5 files may not be converted to PS6 files, however, there is no reason why you should not install PS5 on the same computer, to supporting your PS5 flies. The two applications can run simultaneously but not with the same oscilloscope.
As such, you may perform measurements with PS6 and view your PS5 files on a single computer.