A new update of the Extras + Info service app for Nokia Lumia brings options for call and SMS blocking. The update is available to all Windows Phone 8-powered Lumia smartphones, but the new functionality works only on those running on the GDR2 a.k.a. Amber update.
Thanks to new APIs coming with the WP8 GDR2 update, Nokia was able to add the call/SMS blocking functionality to its latest smartphones. Currently, Nokia Lumia 1020 and Lumia 925 are running it officially, while the rest of the Lumia WP8 gang (920/820/720/620/520) will be getting it any moment now.
In case you are running WP8 with Amber (GRD2) on your Lumia, then you can update your Extras + Info app. Then go to Settings, Extras + Info and find the call + SMS filter. Here you can add numbers and all incoming communication from those will be ignored automatically.
You can find the updated app here.
Source | Via