Topfield's site is (currently) listing a firmware for the "TF5800PVRt" which can be forced on to the TF5800 (using tools like HDFWv2) and has Series Link functionality in it. This may be an early test firmware that has somehow escaped on to the web site -- I'm sure the status will be confirmed soon. As it (a) has the wrong system ID and (b) changes the layout of things in your flash memory, you need to be pretty sure you want to try it and you need to (at present) perform a Factory Reset and then a channel scan once you have managed to install it. Beware that as well as the benefits of Series Link there are a number of other changes, such as double the number of timers (140) and greatly increased memory usage (which may need settings to be changed for some greedy TAPs).

I would recommend that unless you're a knowledgable user, you don't play with this one. It's almost certainly (the only reason I'm not 100% certain is the time difference with Korea) not meant to have been released and it's not anywhere near the final version, because I know there are more changes to come.