This thread (https://forum.cyberlink.com/forum/posts/list/84803.page#350684) in March 2021 seems to indicate that it is not available in the licensed versions but only in 365.
However, this thread (https://forum.cyberlink.com/forum/posts/list/85915.page#355674) in Oct 2021 is showing a demonstation of the feature in Version 20 Ultimate.
And there seems to be no definitive answer if AI Sky Replacement is available on the V20 Ultra. The "Plans and Pricing" web page at https://www.cyberlink.com/store/powerdirector-video-editing-software/buy_en_US.html show that "Advanced features (e.g. AI-powered tools, selection mask (vertex), shape designer etc)" are not in the Ultra version. But to me, that is not clear if AI Sky Replacement is to be considered an "advanced feature" or not. If it is, then what other things are considered an "advanced feature" that would be missing from the Ultra version? Why does Cyberlink not make this clear?
A little clarification would be helpful.