Justshop menu card update
In earlier version of Justshop theme (prior to mid 2015) I used to bundle a premium plugin for managing Menu cards.
Unfortunately the developer of the plugin I paid for (in order to make my theme customers to use it) abandoned the plugin and no support/update is available anymore.
I am not in position to maintain the plugin as it was not my work originally.
So I had to discountinue the menu card plugin from version v6.0 onwards.
I suggest you can switch to free plugin https://wordpress.org/plugins/food-and-drink-menu/ which is independent and appears to be well supported as they have paid version too.
I apologise for extra work and efforts it might take for you to switch the Menu items to a new plugin. But it will be the last time. As that plugin is independent, you can switch theme later and still have your menus intact.
Thanks for your understanding and feel free to contact me from here http://templatation.com/support/ if you have any questions.