Will I lose content of Custom CSS section if I upgrade

I am an intermediate user of Word Press but not very technical. I acquired V3.2 of Catchbox Pro in May 2014 and was contemplating upgrading to the current version of 4.3.2. No specific reason but just to be up to date. Will I lose the content of the Custom CSS section or will the customization itself not work any more because it is applicable to an older version of the software. Adam