From Canon UK:
Canon adds new functionality to the EOS C300 and EOS C300 PL
United Kingdom and Republic of Ireland, 18 May 2012 – Canon today announces the availability of a new firmware update for the ground-breaking EOS C300 and the EOS C300 PL. The update, version 1.0.5.1.00, will add Genlock synchronisation for 24.00P, 24.00PsF, 23.98P and 23.98PsF signal inputs. In addition, the new firmware will add support for Korean language to the menus.
The new firmware will be available from the end of May 2012 from http://software.canon-europe.com/