Nokia has released a new software update for the Lumia 710. You should be running OS version 7.10.8107.79 and firmware version 1600.3013.8107.11502 after the update. The update can be downloaded via Zune or Windows Phone 7 Connector for Mac.
The changelog looks as this:
Improved service calls to numbers that include the characters * and #
Improved usability with text messages (international characters, longer messages)
Improved sound quality with built-in speaker
Latest version of the operating system Microsoft 7.10.8107.79