It took a day after the release to find out about it but Microsoft has posted information on the Windows Phone Update Page about the 7740 build that was released yesterday. The build was found to be available for HTC and Samsung devices but not all of them. Based on Microsoft’s posting, it looks like it was aimed at mostly European models.
Email threads. 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.
Voicemail. Fixes a voicemail notification display issue.
This update is available only in certain markets.
While it is a day later than expected, Microsoft has one again proven they do provide information on what the particular builds released are fixing or adding to the Windows Phone platform.