You are basically saying that you are relinquishing your copyright after 2020. It is now 2022. It is no longer copyrighted according to your notice. (although does not apply in countries subscribing to the Berne Convention anyhow)

(IANAL etc)

Refs: https://www.thesmartbear.co.uk/copyright-your-website-content-the-right-way/, although I concede that they state it's a matter of freshness, not perceived legality. It might be questionable if you released any changes in patches since 2020 though, as yer explicitly excluding them. It'd at least be an ajar door in litigious jurisdictions like the States. https://photocopyrightlaw.com/can-i-use-a-range-of-dates-in-a-copyright-notice/ makes the most important observation though: "Keep things in perspective. Copyright notice is not a legal requirement. You could have no copyright notice whatsoever and your photographs would still be protected by copyright. The only purpose of a copyright notice is to inform viewers of an image that it is under copyright protection, and prevent them from claiming ignorance." (this is the Berne Convention thing I mentioned) Either way, it's just a website 101 gaff to have an outdated year there. Makes Adobe look a bit daft when it's the admin app for their own dynamic-web-site-making software.