The Jelly Bean OS for Micromax A110 is out and there is nothing official about it. In other words it’s the Mobistel Jelly Bean ROM and nothing to do with Micromax. Updating to any 3^rd party ROM will void your warrant and there is a risk, if you can take.
One again, proceed at your risk though the chances of failure are less, but you never know. If you are willing to take the risk and upgrade your Micromax A110 to Jelly Bean OS, read on.
The process is much simpler than as seen with the V2 ROM upgrade. You need to download the Jelly Bean ROM from here CynusT2JellyBean_V15.01.zip remember this is not the official Micromax JB ROM.
Once you download the file that is over 200 MB, place the ZIP file on the internal storage or the external storage, I prefer the internal storage, make sure there is plenty of space on the internal storage cause the 1.5GB is allocated for phone storage and 1.48GB for apps.
How To install Jelly Bean OS on Micromax A110 (Please read the full article before applying the update).

• Make sure the battery level is over 60%.
• Copy the zip file on to the internal SD card.
• Shut down the handset.
• Press volume +, volume – and power button simultaneously and keep pressing until you see two options.
• Use the up or the + volume button to enter recovery mode.
• Now select apply update from SD card and choose the CynusT2JellyBean_V15.01 file. For moving up and down use volume buttons and for selection, use the context button or the left square dedicated button.
• The update will start, will take few minutes. Then restart the phone and all the apps on the phone will be optimized for the JB OS.

Though most or all of your apps will work, but better take backup of important files & contacts etc. if needed.
After the update

• Quadrant score = 2586.
• Antutu Score = 6830.
• Nenamark2 = 22.9fps.
• Internal storage for apps = 1.2GB (332MB used).
• RAM 176MB free (311 MB used).
• 1.05GB as phone storage.

One of my SIM card did not work – failed to show the network, I tried another SIM card and that worked. In fact both the SIM’s that worked were  64K SIM. If you are using older SIM card then probably it might not work, better upgraded the SIM or don’t update to Jelly Bean OS.
The performance is good, image quality seems a little better, sound is as it was before. I have just updated, will use the new OS for some time / days and will updated this page as soon as I find any issues or something good about it.