The IRremote Library is using a old version 2.0 code please update it.

[Dibhav]

Thank you for using the IRremote library!
It seems, that you are using a old version 2.0 code / example.
This version is no longer supported!
Please use one of the new code examples from the library,
available at "File > Examples > Examples from Custom Libraries / IRremote".

Start with the SimpleReceiver or SimpleSender example.

The examples are documented here:
https://github.com/Arduino-IRremote/Arduino-IRremote#examples-for-this-library
A guide how to convert your 2.0 program is here:
https://github.com/Arduino-IRremote/Arduino-IRremote#converting-your-2x-program-to-the-4x-version