Just found some references to "enable-a5-2-ciphering" to be placed in customization.xml while doing some googling...
"If you got your own custpack, add this line in <network> </network> tags, near start of CUSTOMIZE.XML file in your customisation:
<enable-a5-2-ciphering>true</enable-a5-2-ciphering>"
But it seems opposite than my problem. As per the error message I'm getting it seems that my phone tries to enable the encryption but the operator is not supporting it. So it is already enabled in my phone. I opened my customization.xml and there was no such line so should I assume that the default value for a5-2 ciphering is true if it is not provided.
If I want to enable it know, would just modifying existing customization.xml in my phone and restarting my phone will turn it on?
I tried using my friend's Vodafone SIM and no such error comes with his SIM. But then it's not possible that AIRTEL stopped ciphering since I flashed as no such error was coming prior to the upgrade.
Any help is greatly appreciated.