The development team at Gmail has revamped codebase, and started rolloing out latest impromvements to Google Apps users. According to a blog post on Official Gmail blog, 

[…]Employees, students and other Google Apps users will soon start seeing useful features like these:

• even faster interface
• group chat from the browser
• streamlined contact manager
• colored message labels
• improved keyboard shortcuts
• bookmarkable messages and searches

If you're a Google Apps administrator and you'd rather start getting new features right away instead of waiting, you can change a setting in the control panel to automatically get future features as they're released.

Google, Gmail, Google Apps