The older tablet and smartphone will remain on Android 4.1 Jelly Bean.
Google has confirmed that the Motorola Xoom tablet and Nexus S smartphone will not receive the latest version of its mobile operating platform, Android 4.2 Jelly Bean.
Jean-Baptiste Queru, the Technical Lead for the Android Open Source Project, confirmed the news in a post on Google's forum regarding the recently released Android 4.2 update. "There is no support for 4.2 on Nexus S and Xoom. Those devices should continue using 4.1.2," he stated.
Both of the aforementioned devices received an upgrade to the original Jelly Bean version, Android 4.1.
Queru, however, did not divulge any information pertaining to the reasons behind Google halting the the updates at Android 4.1.2 for the devices. Android 4.2 isn't a considerably major jump from its predecessor so the firm's decision is a surprise.
The latest Android operating system, which has had its security features improved, recently launched on Google's Nexus 4 smartphone and its Nexus 10 tablet.

I believe when iOS devices are updated, the older models dont get all the features of the new OS. The same is not true for Android.
Im sure the good guys at xda will get 4.2 to these two devices. Anyway the jump from 4.1 to 4.2 is not as huge as the jump from 4.0 to 4.1. I'd be happy with 4.1 if I owned the nexus s