TVs that shipped with Flash Player cannot have the Flash Player Version updated.
Why? When you download Flash Player for your Web Browser of your Computer, there are different versions for each browser.
Due to the low demand for Flash Content on TV browsers, and the advent of HTML5 video (adopted by Android and iOS already), new versions of Flash Player are not being created for smart TVs.
That being said, webOS TVs are compatible with HTML5 video.
Many sites that use Flash content, also offer an alternative in HTML5 for mobile users, or desktop users that don't want to install Flash.