Although bulk importing of extensions is currently supported, the current .CSV does not include phone codec and priority as an option. Therefore, once you import the .CSV you must manually edit each extension to add the appropriate codecs. Currently (v15) there is not an option to edit multiple phones at a time, like you can do with the 3CX Client, which makes editing and importing hundreds of phones at a time very time consuming. Please consider adding this feature, as it will save lots of time when making bulk changes. Thank you.