Apple has stated that they will be masking IP addresses of email users so this will limit information on opens and our ability to detect other information that we use for contextual widgets (time, weather, location). It seems Apple will use different proxy servers around the world and each recipient should be redirected to the nearest proxy to them. So far it seems that the country is always correct, but you cannot count on knowing more than that. City-based targeting cannot be relied upon. It seems plausible that Apple will have a proxy in major cities around the world (e.g. London, New York, etc.) and those opening from those cities could have a right match also for the city. However, at this stage it is too early to test this fully.