While Microsoft has not released any official statement about the build even for them Windows 10 Insiders, unofficial sources have leaked Windows 10 build 10558. This build has a number of notable and interesting changes. 
Let's see what's new brings the build leaked:
A big change in Windows 10 build 10558 is the addition of the Universal / Metro "Messaging" application.
You may remember that the Windows 8 είχαν μια Messaging εφαρμογή που αργότερα αφαιρέθηκε. Επίσης, οι εφαρμογές του Skype και του Microsoft Edge were informed.
Microsoft seems to be trying very hard to develop the new browser. In this release, Edge comes with the following changes:
- Tabs with Previews. All browsers have this capability, and Edge now has it.
- An interface for the Download Manager was updated.
- An Developer Tools UI was updated
Users who have already installed the new build have noticed improvements in browser performance. However, it could be a placebo effect and we can not guarantee it if we do not install it.
The new messaging application will unify all your conversations from various applications and sources like Skype, SMS and more in a single application.
The context menu has been updated. It became a little smaller and has a more sophisticated look.
The Spotlight feature, which changes the background image of the screen locking χρησιμοποιώντας αυτόματα τις εικόνες που κατεβάζει από το Internet, είναι διαθέσιμη για την έκδοση Windows 10 Enterprise.
A new security feature has been added to the Settings application. It's called "Find my device."
In addition to these changes, Windows 10 build 10558 has a lot of new icons.
Η διαρροή προήλθε από τον γνωστό Ρώσο leaker Wzor. Να αναφέρουμε ότι το ISO δεν είναι επίσημο. Οι ενδιαφερόμενοι μπορούν βρουν το download link to Wzor's tweet.
megahttps://t.co/iPjooHn4gu
cldhttps://t.co/tGu0K7AkKX
magnet:?xt=urn:btih:FF6C98DD6EF5FD926613DF48C5D3A5DD34739D22 pic.twitter.com/rXBQHDtY8k- 🔮WZor👁️ (@WZorNET) October 3, 2015
