Identifying what values can be returned using GetUserCountryCode.
Our country codes do not include countries in which Roku is not yet selling retail devices. For regions where Roku has not yet entered the marketplace (of which Poland is one) it should return "ot," which represents Rest of World.
You can find a complete list of country codes on our SDK documentation here.
Full list of country codes, as defined in Channel Analytics, can be found on our Developer Docs here.