Win10 update: Microsoft Xbox One explains how to arrive to members preview
First, Ybarra explained that the release will be done in a staggered: it is a massive update and extremely important, within the next two weeks will be made a first release focused on the preview program members who in the past have issued many warnings and thus contribute to solving problems. The goal of the developers is to quickly receive several reports on the new update so as to correct any problems, after which the update will be released gradually to others.
The release will not be automatic: preview program members will receive a message on Live that invite to open the Preview App will find a page here that will enable you to choose whether you like it or not this update, and if you decide to not continue to receive subsequent updates but will be excluded from this particular test. If you agree, will have to wait their turn for downloading the update.
If you do then the preview program, cross your fingers hoping to receive it in the first waves: otherwise you may arrive in October.