Bitcoin Forks

Each Bitcoin node decides which version of the software it wants to run and use for validation of the blockchain.  Whenever there is a change or deviation in the internal code of Bitcoin, it creates what is known as a “fork”.  Sometimes these forks are expected and agreed upon by the majority of nodes; sometimes they only gain limited support.

Guide - What is a Blockchain?
What Is a Blockchain?
Guide - What is Bitcoin?
What Is Bitcoin?