Microsoft has started distributing a new operating system update for Windows Phone 7.5.
The update brings the operating system version up to 7.10.7740.16 and appears to be available for a variety of devices. Build 7740 addresses some issues with Microsoft Exchange 2003 and a voicemail notification problem:
- Fixes an email issue related to Microsoft Exchange Server 2003. With this fix, when you reply to or forward a message, the original message is now included in your response.
- Fixes a voicemail notification issue
Windows Phone users originally reported an issue with Exchange 2003 where replies to emails never included the original message. Microsoft has moved quickly to address this bug but the software giant is still investigating two other problems with Windows Phone 7.5. Microsoft confirmed in October that it is investigating instances of the Windows Phone 7.5 “Mango” keyboard disappearing during use. The problem appears to be related to background tasks from certain applications. Scheduled Tasks or Background Agents allow an application to execute code in the background, even when the application is not running in the foreground. HTC devices include a background agent for the Hub and a number of third party applications utilise the support to update Live Tiles and other parts of applications. Disabling individual background tasks appears to fix the issue.
Microsoft is also investigating reports of Windows Phone 7.5 locking up or freezing during Zune music playback. A number of threads existing with hundreds of replies on Microsoft’s own support forums concerning the problem. Microsoft confirmed to WinRumors in October that the company is aware of the issues and is investigating them to determine the root cause. The vast majority of affected users reporting the problem are using HTC devices.

Windows Phone 7.5 build 7740