(Please use this template for reporting issues. You can delete what ever is not relevant. Giving us this information will help us help you faster. Please also read the FAQ & Troubleshooting Guide. Your problem may already have an answer there.)
Typically located in the library.json & src/IRremoteESP8266.h files in the root directory of the library.
e.g. v2.0.0, or 'master' as at 1st of June, 2017. etc.
What steps did you do and what should it have done?
e.g.
What steps did you do, and what did or didn't actually happen?
e.g.
Include some raw dumps of what the device saw.
What can we do to (pref. reliably) repeat what is happening?
Include all relevant code snippets or links to the actual code files. Tip: How to quote your code so it is still readable.
Link to an image of the circuit diagram used. Part number of the IR receiver module etc.
Yes/No.
Yes/No. If "Yes", which version last worked for you?
More information is always welcome. Be verbose.