Although the PadFone 2 already got it's Jelly Bean update late last year, the original PadFone was still working on Ice Cream Sandwich. That will change very soon. Asus is pushing out Android 4.1.1/Jelly Bean to the PadFone now. Here's a quote with the scoop, followed by a link where you can download the update,

PadFone Firmware: V10.2.1.9 (Android 4.1) improvement:
1. OS upgrade to Android 4.1.1
2. Improve dictionary function
3. Improve Camera preview function
4. Improve Scrapbook function
5. Improve File Manager application
6. Improve Volume Key problem
7. Support SD card NTFS & EX Fat format
Although this one is a bit later than usual, one of the best things we can say about Asus is they send out timely updates to their devices for the most part.

Source: Asus Padfone Support Website