Hi…update of visual composer needed with urgency

HI…I’ve bought Fortuna a while ago but I’m developing the website right now. I’ve updated the theme to version 1.5.0 and visual composer version is 4.8.1.
The Visual Composer is not working correctly, i try to add an element like row or text and the composer does nothing, so i need to update it to an upper version, if not the latest.
I also encountered this visual composer problem with another template, and an update to the plugin did the trick.
How can i update it?
By the way there is no update button on the plugin.