You need some kind of special decoration for "you buy a license to use the app, not a specific version of the app", like VueScane or FL Studio (you pay for a lifetime license to "the thing", not "whichever version of the thing happened to be the current version when you bough it").
And maybe a badge of shame for "buy once, and yeah, you own that version, but you get punished for not upgrading by skipping a version meaning you now pay full price again" like DxO... Yeah it's "you own it" but my goodness is it the worst possible way to offer that.