Well, there is quite some difference between what the agile manifesto describes and what the 5000-page Agile Handbook (TM) of some international consulting firm describes.
The original agile manifesto though is still valid. Guiding principles is all you need
He calls this the agile industrial complex and says that anyone using agile with capital A is not referring to the manifesto but the industry and are selling you that.
Agile is Dead - https://www.youtube.com/watch?v=a-BOSpxYJ9M