How to update Cordova?

Hi everyone!

Thanks for this great great framework7!
I want to install a cordova plugin like
framework7 cordova plugin add cordova-plugin-customurlscheme --variable URL_SCHEME=mycoolapp

Problem is only since Cordova 3.6 --variable is allowed (I get error: unknown option ‘–variable’).

My question: How can I upgrade framework7 cordova (currently 3.1) to 3.6?

Much love,