The version history of the
Windows Phone operating system began with the release of Windows Phone 7 in October 2010.
Version history Edit
Windows Phone 7 Edit
Table of versions: Windows Phone 7
Windows Phone 7
initial version of the Windows Phone 7 OS
improve update process for future update
Added CDMA support, Copy and Paste, fast application startup, and deeper Facebook Integration
revoke of fraudulent certificates
intermediate update required for updating to Mango
Windows Phone 7.5 Edit
Table of versions: Windows Phone 7.5
Windows Phone 7.5" codename " Mango" was announced in February 2011 at the Mobile World Congress. The update was formally announced in New York on May 24, 2011, when Microsoft gave an in-depth preview of the update, shortly before which Steve Ballmer had disclosed that there would be over 500 features. Although the OS internally identifies itself as version 7.1, it is marketed as version 7.5 in all published materials intended for end-users. 
Microsoft started rolling out Windows Phone 7.5 to both the United States
and International  markets on September 27, 2011. The first phones that came pre-loaded with Windows Phone 7.5 were released in the last quarter of 2011.
September 27, 2011
Messaging and social integration
Dynamic Live tile information
Twitter and LinkedIn integration in the People hub.
Groups: organize contacts by groups which can also be pinned on the start screen.
Contact cards now include all the contacts conversation history (SMS, emails, MMS, Messenger, etc.)
Facebook Places check-in support.
Windows Live Messenger and Facebook Chat integration.
Threads: all messaging communication organized in a single thread (Messenger, SMS, MMS).
Threaded email conversations support.
Outlook tasks support.
Facebook events integrated into the calendar.
Linked email accounts: multiple email accounts can be combined and linked into one inbox.
 Built-in voice-to-text/text-to-voice functionality, which will allow for hands-free texting or chatting.
Server search for Exchange.
Information Rights Management support for emails and Office documents.
Bing Vision: barcode, covers, posters, products scanning, and OCR text translation.
Bing Audio / Music: Shazam-like audio recognition.
Bing Local Scout: "around me" business and POI locator.
Bing Quick Cards: product/media information, reviews.
Bing Search: indoor maps (US only), image search results, third-party app integration.
Bing Maps: turn-by-turn navigation, voice guidance.
Skydrive and Office 365 documents sync (PDF also supported).
 Excel Mobile now supports adding additional macro functions.
Microsoft Lync support via downloadable app.
Added "To-Do" option when editing OneNote pages.
Removed ability to edit Office documents from versions older than Office 2007.
People / Groups gallery with Skydrive and Facebook sync.
People tagging in the photos with Skydrive and Facebook sync.
 Photo auto-fix - automatically improves sharpness, brightness, etc.
 Pictures tile is now animated.
Video sharing via MMS, Facebook, Skydrive, and email.
 Twitter integration—Tweet your pics!
 Integration with the People Hub.
 Quick access to the Camera Roll.
 When you choose a photo from within an app, you can now pick from online albums on Facebook or SkyDrive, not just pictures saved on your phone.
 Pin any album to Start, including Facebook albums.
Zune SmartDJ mix support.
Artist picture now displays on lock screen when music is played.
UI change of the media controls on the lock screen.
Ability to control video aspect ratio during playback.
Single music track repeat without having to pin it on the start screen.
Podcast downloads / subscriptions over the air (US only).
Open / play media content by voice.
Ability to create and save playlists.
Revamped Marketplace UI and search.
UI changes (new icons + added arrow icon on the lower left of the viewfinder to indicate camera roll).
Settings are now saved when the Camera application is closed.
Disable/enable shutter sound.
Support for front facing camera.
 Touch focus and capture—Tap any spot on the screen to focus there and take the shot. (This varies according to hardware—some phones will have tap-to-capture but will still automatically center focus.)
 Review pictures above the lock—Snap a photo when your phone is locked, then take a peek at it above the lock. You’ll only be able to get to photos you just took—better for security.
 Changes for portrait orientation—Now, when you take a picture in portrait orientation, you’ll see it in portrait orientation when you review it.
Redesigned Games hub with integrated 3D avatar and avatar customization.
 Friends and achievements now integrated in the hub.
Fast Async for multiplayer games.
Internet Explorer 9 Mobile
Support for HTML5 audio and video playback.
Background HTML5 audio playback.
New UI with URL bar at the bottom of the screen.
URL bar is now available in landscape mode.
Removal of Find on Page feature
 Moved the "tabs" button to a menu item under the application bar.
Voice commands are now disabled when the device is locked.
Complex (alpha-numeric) PIN support.
 Battery saver: phone automatically disables power consuming services and applications running in the background if the battery is low. Also predicts time remaining on battery.
Ringtone manager with custom and downloadable ringtones.
The "People" tile has been reworked and is animated differently than before.
Search icon and quick jump list added to the application list.
Support for 16 new languages: Czech, Danish, Hungarian, Dutch (Netherlands), Norwegian, Polish, Portuguese (Brazil, Portugal), Finnish, Swedish, Greek, Russian, Korean, Chinese (Traditional, Simplified), Japanese.
East Asian handwriting recognition.
Support for new languages and emoticons in on-screen keyboard.
Hidden WiFi network support.
Qualcomm MSM7X30 and MSM8X55 support.
Programs menu will have alphabetical options similar to the people functionality
 Power off now requires a swipe down gesture after holding down the power button for a few seconds.
Removal of "soft-on" alarm feature
 Modification of alarm sleep interval
Development API changes and additions
Third-party application multi-tasking and fast application switching.
Support for background tasks and services/agents.
Expanded live tiles that can be updated without network connection and can have two sides which flip periodically.
 App Connect: third-party applications can integrate with Bing search, have multiple live tiles, and can have push notifications that link deep ("Deep Toast") into various parts of the application directly.
Optional 32 bit color support for Silverlight applications with hardware dithering.
Silverlight 4 support.
Silverlight + XNA support in the same application screen.
Raw camera feed access for third-party applications.
New sensor API combines compass, gyroscope, and accelerometer.
Improved Listbox control with better scrolling performance.
Improved WebBrowser control with IE9 rendering engine and system-wide cookies access.
Hardware-accelerated video decoding in the MediaPlayer control.
TCP/IP and UDP sockets support.
Embedded database with LINQ (based on SQL Server Compact 4.0 engine, but without direct SQL execution).
Background file transfer agent.
Generational garbage collector.
NEON/SIMD support for XNA applications.
7.10.7740 Edit Unknown
Fixed email issue in Microsoft Exchange Server 2003
Fixed voicemail notification issue.
Fixed keyboard disappearing bug
Fixed location access issue
7.10.8112 Edit Unknown
Initial release for AT&T Nokia Lumia 900 & HTC Titan II.
June 28, 2012
Better media messaging
Ability to send ringtones via MMS
Export and manage contacts to SIM card
Support for low-cost devices with 256 MB RAM and low clock CPU.
 New wallpapers
More reliable notifications
Attachment download with Microsoft Exchange 2003 Server
Faster numeric PIN response
 Location awareness icon
 Minor improvements and changes
Also confirmed are 23 additional markets
including; Bahrain, Bulgaria, China, Costa Rica, Croatia, Estonia, Iceland, Iraq, Israel, Kazakhstan, Latvia, Lithuania, Qatar, Romania, Saudi Arabia, Slovakia, Slovenia, Thailand, Turkey, UAE, Ukraine, Venezuela and Vietnam. This update will also include a Skype application.
The  Nokia Lumia 610 and ZTE Orbit, introduced at Mobile World Congress in 2012, are the first phones to run the mango update.
Fixes an issue with app purchases in some regions.
Changes default sync times for email.
Provides support for phones without physical camera buttons.
Provides other Windows Phone improvements.
Windows Phone 7.8 Edit
Table of versions: Windows Phone 7.8
This version does not support USSD.
Previously released Windows Phone hardware is incapable of being upgraded to Windows Phone 8, due to changes in the
kernel requirements and hardware specifications. However, Microsoft announced at the Windows Phone 8 announcement event that Windows Phone 7.x devices would receive a free upgrade to Windows Phone 7.8. Nokia's first flagship Windows Phone Lumia 900 has been updated to Windows Phone 7.8 update in several countries. The update includes some of the features present in Windows Phone 8, including the revised start screen and additional unspecified functionality. 
7.10.8858.136 Edit February 1–2, 2013
New start screen UI with customizable sizes of the tiles, as found in Windows Phone 8
New splash screen at startup, the phone displays the new logo of Windows Phone 8
New logo for basic applications such as Games, Office, Windows Phone Store
20 accent colors (one for the manufacturer or the operator), as Windows Phone 8
Improved lock screen similar to Windows Phone 8, presence of dynamic wallpaper (Bing) notifications and probably third-party applications
Volume control problems
 Data consumption issues with certain apps
7.10.8860.142 Edit March 14, 2013
Features "several quality improvements"
Enabled Tethering Wi-Fi in Samsung Omnia GT-I8350
7.10.8862.144 Edit March 14, 2013
Windows Phone 8 Edit
Table of versions: Windows Phone 8
Windows Phone 8
Windows Phone 8 (codenamed Apollo) is the next generation of Windows Phone, as officially confirmed by MS at an MSDN seminar in August 2011 and previewed at Microsoft's 'sneak peek' at Windows Phone on June 20, 2012. Devices will be launched by four companies,
Nokia, Huawei, Samsung and HTC and others include Acer Lenovo and ZTE. All devices will be based on System on Chips from Qualcomm (Snapdragon S4 Plus). Current Windows Phone 7.x devices will not be able to run or update to Windows Phone 8 and new applications compiled specifically for Windows Phone 8 will not be made available for Windows Phone 7.x devices.
GDR3/Update 3 update is possible to install on any Windows Phone with GDR2 by registering for a free Microsoft App Studio ID, installing the certificate sent by email (not necessary) and lastly installing the Preview for Developers app  before checking for updates in the settings menu on Windows Phone. However, this may void the OEM and carrier warranty of the device.
29 October 2012
Transitions to core components from Windows 8, including kernel, file system, drivers, network stack, security components, media and graphics support
Support for multi-core CPUs of up to 64 cores (system is currently optimized for Snapdragon S4 dual and quad core processors)
Support for WXGA (1280×720, 1280×768) resolutions
Support for MicroSD cards
Internet Explorer 10
Background multitasking (enhanced)
NFC support added, including payment and content sharing with WP8 and Windows 8 machines (NFC is partially supported in Tango update, e.g. ZTE Orbit)
Native code support (C and C++), simplified porting from platforms such as Android, Symbian, and iOS (Native code is also supported in WP7 for vendors, carriers and key partners)
Simplified porting of Windows 8 apps to Windows Phone 8 (compatibility with Windows 8 'Modern UI' apps)
Carrier control and branding of "wallet" element is possible via SIM or phone hardware ( Orange will be first)
Nokia map technology ( Navteq maps with offline mode, turn-by-turn directions)
Native 128-bit Bitlocker encryption, Secure Boot
Remote device management of Windows Phone similar to management of Windows PCs
VoIP and video chat integration for any VoIP or video chat app (integrates into the phone dialer, people hub)
Firmware over the air for Windows Phone updates
Minimum 18 month support of Windows Phone updates to WP8 devices
Camera app now supports "lenses", which allow third parties to skin and add features to camera interface
Camera burst mode that let users choose the best picture from a series of pictures
Camera panoramic setting using Microsoft's PhotoSynth technology
Possibility to take screenshots
Deeper SkyDrive integration, including ability to sync data such as music collections
Data Sense tracks and reports data usage, lowers data usage when nearing pre-set data cap, enables compression of websites through cloud service, locates WiFi hotspots
Scrapped Zune desktop software for syncing
11 December 2012
Messaging improvements - multiple recipients when sending messages, automatically saving unsent drafts, possibility to edit forwarded messages
 Text replies to incoming calls
Internet Explorer improvements - prevent pictures from downloading automatically, possibility to delete selected sites from browsing history
Wi-Fi connectivity - option of keeping WiFi alive while screen is off, Wi-Fi network prioritization
Other unnamed improvements
12 July 2013
Google accounts. Windows Phone 8 now supports the CardDAV and CalDAV protocols that allow people to sync Google contacts and calendar information when they get new phones.
Xbox Music. Easier to select, download, and pin music. More accurate metadata and other performance improvements.
FM radio. Possible to listen to FM radio from the Music+Videos hub. (Not available for all phones.)
Data Sense. Possible to set a limit based on the data plan (already included since initial release for Verizon subscribers)
Skype. Voice over Internet Protocol (VoIP) apps like Lync and Skype features improved stability and performance.
Internet Explorer. Better browsing experience with improved HTML 5 compatibility.
Camera. Set favorite Lens so it opens automatically when pressing the camera button. (Not available for all phones.)
Other improvements. Includes many other improvements to Windows Phone.
 14 October 2013
Support for large displays and start screen with six tiles across instead of four (only for supported devices)
1080p screen resolution support
Support for Qualcomm Snapdragon 800 SoC ( Quad-core CPU)
New Driving Mode feature to ignore texts, calls and quick status alerts, plus auto-reply via SMS to people trying to contact you
Accessibility improvements for visually impaired
Improved Internet Sharing (pair over bluetooth with Windows 8.1 devices and ICS is set up automatically)
Ability to leverage custom notification sounds, including instant messages, emails, voicemails, reminders and custom ringtones to contacts for text messages
Screen Rotation lock
Better storage management
Ability to close applications in app switcher
Wi-Fi access during phone set up
Bluetooth bug fixes and improvements to connection quality for Bluetooth accessories
"Hundreds of under-the-hood performance tweaks and enhancements"
Windows Phone 8.1 Edit
Table of versions: Windows Phone 8.1
Windows Phone 8.1
Windows Phone 8.1 (codenamed "Blue") is Microsoft's next major update to Windows Phone. The focus of the update is to improve upon the lack of much basic functionality found in competing Android and iOS operating systems and to continue the unification of Windows Phone with Windows to comply with Microsofts goal of one operating system.
On February 10, 2014 Microsoft started sharing its Windows Phone 8.1 Software Development Kit (SDK) with developers and the changes and new features for Windows Phone 8.1 in the list below have since been confirmed.
Documentation for the SDK also confirms that all current Windows Phone 8.0 devices will get the 8.1 upgrade. Windows Phone 8.1 apps will not run on 8.0 devices.
2–4 April 2014
Action Center showing actionable (if developer enabled) notifications, accessed by swiping from top to the bottom
Quick settings access in action center with four configurable shortcuts to: Bluetooth, brightness, camera, flight mode, internet sharing, location, project screen, rotation lock, VPN, Wi-Fi
Start screen backgrounds
'Cortana' smart agent performs the same tasks as Siri and Google Now and even more, including data from Foursquare
Swipe down to close apps in multitasking view
Silent notifications which go directly to the Action center
Filter through installed apps by usage/install date
Possibility to mark a Live Tile as read by swiping from the left of said tile
Support for virtual on-screen buttons called 'Navigation bar'
Navigation bar color selection
General user experience changes
Bing smart search (similar search system as Windows 8.1)
Back button doesn't close application
Contact speed dialing
Contacts only with phone number shown
Contacts with inner circle; up to 40 contacts
Double-Tap to unlock your phone (Feature from Lumia devices on Amber Update and newer)
Double Tap to Power Off
Favorite photos by tapping a heart icon
General keyboard enhancements, show emoji when typing
In-call speech commands
Kid's Corner - Password won't be displayed (bug fix)
Notification if charger isn’t of adequate power
Quiet Hours - Disable notifications during pre-selected timeframe
Screenshot button combination is now Power + Volume Up
Search button will be the new way to open Speech (aka ‘Cortana’)
Separate volume controls for ringtones/notifications and music/media
Set default Voice Navigation app for the OS
Voice Narrator for Accessibility
USB action choices
Wi-Fi Sense: sharing secured WI-Fi Networks with contacts if they have Wi-Fi Sense
Wi-Fi can auto re-enable after a set duration of time
New technology support
VPN (Virtual Private Network), auto-triggered VPN
Wi-Fi Direct, allowing direct peer-to-peer connections over Wi-Fi without an access point
Enterprise Wi-Fi support with EAP-TLS
Miracast; PlayTo and mirroring of Windows Phone screen to TVs and/or monitors
Bluetooth 4.0 LE
Mouse and keyboard (HID)
Support for Qualcomm Snapdragon 200/400/400 LTE
Full support for TD-LTE and SGLTE
Internet Explorer 11
File downloads to local storage
Tab function replaced with multitasking view
Video player including HTML5 video support (video playback doesn't have to be full screen)
Ability to install apps, save photos, app and game data on inserted SD Cards (apps on SD Cards only allowed from one originating phone)
Auto-updates for apps (like Windows 8.1), including when only on Wi-Fi
App Suggestions by location
Better backup functionality including app and game data to OneDrive (if developer enabled)
Battery power sense, monitors app battery usage
Battery Saver (under Battery Sense) will have an app exclusion list
Single sign-in for apps (like on Windows 8) with Microsoft Account; sign in will persist across devices + apps with permissions prompt
Possibility to change default texting application
Podcast app powered by Bing, full featured
Facebook and OneDrive photos integration in photos app removed
Facebook account option removed
Facebook app comes with OS, updates independently
Office apps support password protected documents
Office Lens support for scanning documents with camera, import into Office with OCR
OneDrive (previously SkyDrive) with integrated file browser (like Windows 8.1)
Twitter integrated more deeply into the contacts Hub
Updated calendar app with weather for days and week view
Updated camera app, similar to Windows 8.1, with burst mode and HDR
Updated email app with ability to always download emails and pictures within them, sync with accordance to usage patterns
Updated messaging app with ability to mute thread
Xbox Music and Xbox Video as standalone apps instead of the Music + Video Hub (allowing more updates to be pushed)
Xbox Game Hub redesigned
Chkdsk for SD cards to ensure card health
The phone will have to update to the latest version before you can restore it to factory settings
Trusted app list for NFC that will remove the need for asking whether you want to open a particular app
Virtual SmartCard support
Wallet supports tickets and membership cards
Ability for operators to install certain applications once SIM card is detected
Ability for operators to control Data Sense limits remotely
S/MIME to sign and encrypt email
Enterprise enrolled phones can have their passwords changed and remotely locked
Access to corporate resources behind the firewall with app aware
Certificate management to enroll, update and revoke certificates for user authentication
Enhanced MDM policies to lock down functionality on the phone for more enterprise control, in addition to richer application management such as allowing or denying the installing of certain apps.
Background tasks: Bluetooth signal strength, Chat message notification, Device connection change, Device use trigger, Gatt characteristic notification, Location, Push notification, Rfcomm connection, System event, Timer
Support for 384×640, 540×960 and 1440×2560 screen resolution
Geofencing API for location-based reminders
Audio/video transcoding (same API as in WinRT), hardware accelerated
Media editing: audio and video effects; slow motion video
Apps can capture audio/video from themselves
XAP file format replaced with APPX (like Windows 8.1)
XNA support removed
Stereoscopic 3D support
New developer tools including: SemanticZoom, DatePicker, TimePicker