This is needed when the strings are encoded in utf8. The encoding is needed for special characters (as simple as é) and smileys. 
In my use case, I only need title, body and big_text (not familiar with the new additions: action, etc.) but any string in the notification could need decoding. 
String X = bundle.getString("X")
X= URLDecoder.decode( X, "UTF-8" );

Medium term, it could be nice to have a tag for encoding in the initial message that would trigger or not a decoding.

Android actions fixes #1

 Fix getEntityFCMToken resolve and update README

Android actions

Fix <application> tag

Fix iOS simulator getEnitityToken

added endpoint

Add missing dependency

Add a missing dependency for `firebase-messaging` as part of the setup steps.