There are rumors going around - and I could swear I saw something official, but I have to look for it - that Early Access will begin a full week before launch (August 20; launch is August 27), with P4 rumored to be starting this Friday (Aug 9), if not right after the Live Letter on Aug 8. Phase 4 is slated to be just a full week long, which means it all but has to start no later than August 13. Since it seems weird that beta phase 4 would end the day before early access begins, that probably means it'll be sooner.