There is no such thing as roundcube webmail 5 or 4. the latest stable version of roundcube is 1.2.4.
If you are using the Larry skin then there is an About button in the top left hand corner of the screen. I think in the Classic skin there is an About tab in the settings section. This should tell you what version you have.
when they have logged into the webmail5 seems the webmail not functionality, they can't click or do anything on the webmail