Upgrade all seems to have gone OK. Not sure how I know that I am now using the 64-bit version of Sooloos as it still just reports as 'System version: 529'; but I guess the fact that it is running ok on QTS 4.3.3.0154 means it must be?

Initially my iPad could no longer find the system core (even after re-installing the app); however rebooting the iPad solved that.