Paolo
OK. I went to the Network Admin, then Plugins. I ticked the GeoDirectory Advance Search Filters (I have version 1.0.6), then in the Bulk Actions drop-down I selected Update. Then I clicked Apply.
It says it was successful. I then returned to the Plugin page and it still shows version 1.0.6. In your list is says the latest one is version 1.1.6
I did this with the GeoDirectory Custom Post Types (I have version 1.0.7) In your list is says the latest one is version 1.1.1