Not to long ago Lenovo introduced the 9 inch IdeaTab A2109 with Android 4.0 Ice Cream Sandwich. Only a couple of months later, today owners of such tablets have reportedly receiving Android version 4.1.1 (JellyBean), firmware build A2109A_A411_03_13_121126_US.
The update is available as always over the air, however if somebody didnt got notified yet, there’s always the manual alternative: Go into Settings > About device > Software updates > Check for updates. If this method doesnt work for you either, there’s a third solution:
Click to download the US ROM
source Lenovo Forums