Mobile-specific signature: To let your recipients know that your email has been written on a mobile device.
Vacation Auto-responder: You can now set your vacation auto-responder from the mobile version.
How to access what's new:
Mobile-specific signature: Press the new settings icon, choose your signature, and then check the box to activate it.
Vacation Auto-responder: In your settings, choose a start and end date and specify your message, just like on the desktop interface.
For more information:
Gmail for mobile: Visit mail.google.com on your smartphone or tablet browser