In fact, Dhanush, who never expected his 'Kolaveri di' to become such a massive hit, sold the rights of the song to Sony Music for a less price. Well, this has clipped his wings and he has no control over the track.
The son-in-law of Rajinikanth has to take permission from Sony Music if he wants to make a new version of 'Kolaveri di'. The other versions have to be made in association with the Sony and not other audio companies. It can also be noted that the actor has lost the rights of the Bollywood version.
With new versions of 'Kolaveri di' taking birth, Dhanush has no choice but can only sing for other versions if Sony Music wishes him to croon and get paid for it.