We have just updated our Florence template, adding the option which allows you to set the mobile menu breakpoint via your template settings (Responsive Options tab). For further details on updating your template may I suggest the following article... https://www.joomla51.com/tutorials/item/updating-your-template
Thanks for telling me. Updated the template (bought new). However, I cannot find any change in the settings. Previously J51_Florence Ver. 1.0 now had Ver 1.0.2 from June 2014, ask for help.