Earlyface

=> First, download IMEI analyser from this Link.
=> Copy the imei below and paste it into the imei analyser.
861143032394005
=> Delete the last three digits and replace it with two random digits of your choice.
E.g from 861143032394005, replace 005 to 28
=> Click on analyse to get the last digit.
=> Copy the new 15digit imei you just analysed and replace your current imei with it. You can check out guide here.
=> After that send join to 141 .
=> If the IMEI is valid, you will be rewarded with 5gb.
Alternative Method To Get Airtel 5Gb
If you were unable to change your imei then follow this second.
=> Input your Airtel Sim into any phone. (even touch light phone will work).
=> Send S(your new imei) to 232.
E.g S861143032392470 to 232.
=> Wait for a reply and send join to 141.
=> If the imei has not been used, you will get 5gb but if it has been used you will be the message " you do not qualify for this offer"
=> Just go ahead and re analyse.
So that's it guys, enjoy it while it last.
Pls don't tell me it's not working because it has been tested before I posted it here.
If you have any question, feel free to ask.