Hi Alan,
I did not think 20.4 and 22.1 was out on the web yet. However, I will check the release notes. They may be the same as the defect fixes in 20.4 were carried forward to the 22.x release. The only difference between 20.3.1 and 22.0 was that 22.0 could be used with the CA+ license so you could try both products.
Kelly
I am an HP employee.