Here is what is new in Windows 10 Technical Preview 10051 for Phones

Microsoft has now published the changelog of all the big new features and improvements in today's update for the Windows 10 Technical Preview for phones.

Windows 10 for phone Build 10051 contains numerous new improvements. Below we are highlighting the main changes.

• Project Spartan: An early version of Project Spartan is available in this flight. It uses our new rendering engine to give greater interoperability with the modern mobile web, and includes early versions of Reading View and Reading List. For now, Project Spartan is not the default browser, and exists side-by-side with IE11. You can find it in the All Apps list and pin it to your Start Screen from there. Please send feedback on sites and design. For more details on Project Spartan on the phone – see this blog post. Be sure to also check out this blog post from Joe.
• New mail and calendar apps: Outlook Mail and Outlook Calendar are the new built-in mail and calendar universal apps for Windows 10. These new apps bring a fresh UI, with a toggle to freely move between your email and calendar without returning to the Start screen. Outlook Mail includes customizable Swipe Gestures, letting you swipe right or left to take actions like delete, flag, move or mark as read/unread. Also check out the new email authoring experience. Outlook Mail leverages the familiar capabilities of Word to create a richer email experience. You can do formatting tricks like inserting tables, adding pictures and using bullets and text. Outlook Mail and Outlook Calendar connects to Office 365, Exchange, Outlook.com, Gmail, Google Calendar, Yahoo!, IMAP, POP and other popular accounts. Please note that to add or remove accounts in Outlook Mail and Outlook Calendar, you do so within these apps. The Email + accounts page has been removed from the Settings app.
• New Phone and Messaging apps: You'll see our new Phone and Messaging apps in this build. Give them a try and let us know what you think. The Messaging app has a new visual design. You can also easily upgrade from a messaging conversation to a voice call with one click of the phone icon in the new app bar. Note: If you are updating a phone from Build 9941 – please see below for a known issue regarding MMS that will require you to go use the Windows Phone Recovery Tool to roll back to Windows Phone 8.1 first and upgrade to this build in order to have MMS working on your phone.
• New People app: The new universal People app has a new visual design but will continue to be the comprehensive list of all your contacts across the services you care about such as Exchange, Outlook.com, Gmail, Facebook, etc. You'll be able to easily manage all your contacts and quickly connect with them.
• New Maps app: The first preview of our new universal Maps app on phone is now available. Maps offers you the features and tools you need to explore and navigate the world. This includes the best maps, aerial imagery, rich local search data, and voice guided navigation experiences from both Bing Maps and HERE maps, integrated together for the first time into a single app for Windows.
• Updated App Switcher: Check out the updated app switcher by pressing and holding the back button on your phone to see your recently used apps. We've added support for landscape when invoked from an app being viewed in landscape. For large phones like the Lumia 1520, we've introduced a new grid layout so you can be more efficient at switching between apps. And we've extended the length of recently used apps to 15.

Some things we've fixed

• We've updated the keyboard layout based on your feedback. The keyboard layout now has period, comma and emoji keys on first page of keyboard. Language switching is enabled by press-and-hold on the &123 key. There is also an option to replace the emoji key with the language switching key.
• We've fixed the Cortana icon resolution so it now scales with tile size.
• We've fixed the issue where the Photos app would fail to launch periodically when attempting to add a photo attachment to an email, OneNote or Facebook item.
• We've fixed the issue where the Microsoft Band wouldn't sync with your phone after upgrading to Windows 10.
• The Photos app's tile will now pick up the phone's theme color before it's launched and then start showing pictures from your collection including OneDrive in the Live tile.

As soon as we have finished downloading our updates, we will post a screenshot gallery, hands-on video, and more details about some of the new individual components of today's update! Stay tuned.

Source: Windows Blog