This news comes almost 24 hours later after HTC confirmed via Twitter that Gingerbread firmware update is coming by the end of the month (this week).Verizon Wireless adds the PDF changelog file on their support webpage for HTC Thunderbolt about the latest update to Android 2.3 Gingerbread firmware build number 2.11.605.3, Baseband: 1.48.00.0906w_1, 0.01.78.0906w_2.
Thunderbolt’s latest update firmware brings the following enhancements: Download Manager App to manage all your downloads from web browsing, a new home screen UI (new widgets, icons, screens with refreshed colors) and dock icons. While in the bug fixes area the update improves data connectivity, audio quality, V Cast tones comes pre-loaded, new Google Books app, force closes errors while using TuneWiki is reduced and audio on Bluetooth Car Kit no longer re-routes to phone when receiving a text message, plus a few more other enhancements.
The update is likely to roll right now for a limited number of users across US, and will spread in waves like always until it reaches all Thunderbolt devices connected to Verizon Network. You could try checking for the latest update OTA (over-the-air).