This key is not valid for this version of the server

Why twonky displays this warning message for some seconds in the bottom of its “Server status” page (ip:9000)?

Is this the version ot Twonky Western Digital provides?

Yes. If the browser is really slow I can see a bottom part of the page with a lot of additional settings (probably the license part?).

Slow browser?  Dies this licence not valid message stay there all the dime or does it appear briefly and then vanishes?

It vanishes after one second. This is not a problem for me while browsing the config pages but I do not know if this problem may affect the DLNA server too.

I would be concerned if that licence message remains on the page.  I’ve had this with a number of web sites I’ve visited where bits that are supposed to be hidden are shown until the browser gets to execute bwowser-side scripts which finish the conditional construction of a web page.  This included showing and hiding stuff.

Ift the DNLA server works as expected then I would not worry about it.