Hi Lene,
well – I can only say that I’m using it on various WP versions on different sites and it runs stable from WP 3.5 upwards
One of my sites is running WP 4.1 – the plugin works there as well.
I rated the plugin yesterday as well with the “works” button for WP 4.1 and hope that others do this too so that you can see the experience of other users here.
Of course I can’t make any universal statements about the compatibility of the plugin and/or give advice to or not to update to 4.1
It’s just my personal experiences I describe here.
Regards Katharina