QNAP, also known as “Quality Network Appliance Provider,” launched firmware version 4.0.0 Build 0411 for its TS-120, TS-220, TS-420, TS-121, TS-221 and TS-421 TurboNAS devices.
As it says in the release notes, this is the initial release for these products so there's basically no reason to talk about improvements or fixes yet.
However, QNAP provided a limitations list. According to this, when using Photo Station (a web album for organizing and sharing your photos and videos on the Internet), the animated thumbnail generation for videos is available on Intel-based NAS only.
The is also a limitation regarding the Media Library which is not supported for Video Station.
Internet Explorer 7, 8 are no longer officially supported and the maximum number of shared file links in Qsync is set to 1000.
If you're using your NAS to monitor or record IP cameras, know that Surveillance Station Pro only supports IE 9/10, Chrome, and Firefox browsers on Windows, whereas or Mac users, please use QNAP Surveillance Client for Mac.
Below is the link to the firmware. Download, install and stay “updated one minute ago.”