I'm with a Lumia 520 running wp 8.1 update 1 and Denim.I'm trying to install WP 8.1 update 2.So,I registered at Windows Insider and chose for the fast ring.My Lumia has started downloading an update already.My question is whether the update I'm receiving at present is WP 8.1 update 2,or it is Windows 10 for phone technical preview?Another question is what is the size of this update?