This could be a hoax on the particular website that you are viewing, which is encouraging you to download a malicious copy of Adobe Flash. If the website is legit, then I would not recommend downgrading your version of Adobe Flash - as this could leave your computer open to security vulnerabilities.
Stick to the latest version, it's probably the website itself that's the problem.
Stick to the latest version, it's probably the website itself that's the problem.