As of January the 1st 2014 you will need version 11, or higher, of Flash in order to run Bredbandskollen. We use functions in Flash that needs this version, which makes it impossible for us to support earlier versions of the plugin.
Unfortunately, this means that some operating systems, like Mac OS 10.5 or earlier, do not work with Bredbandskollen. This has to do with the fact that Adobe has chosen not to update flash for these operating systems.
This also means that some equipment with flash built into it no longer works, i.e smart TV-sets. You could contact the manufacturer and check if there is an update available.
Today Bredbandskollen runs on all moderns systems and web browsers, including Windows, Mac OS and Linux. The support is limited for older browsers though.