Thank you, if it's before 1.0 then it shouldn't need version checking anyway for my use. I'd read the discussion on GitHub and seen the reference to CatchableError in the docs as a class, but it's not shown being used in the specific syntax mentioned by the warning alongside the description of except and it wasn't clear to me if that had been introduced along with the warning.
<https://nim-lang.org/docs/manual.html#exception-handling>
