The Bitcoin Core Project issued a statement saying that Bitcoin is a network defined by its users, and users have the ultimate freedom to run any software they want to use (whether or not it is fully verified) and implement any policies they are willing to follow. Contributors to Bitcoin Core have no right to force decisions on what rules users must follow. This principle is reflected in long-term practice: Bitcoin Core software does not support automatic updates. This means that no entity can unilaterally force changes to Bitcoin Core users. All changes must be made by the user's proactive choice to upgrade to a new software version or to select a different software. This freedom to run arbitrary software is the main guarantee for the Bitcoin network to withstand external coercion. "As developers of Bitcoin Core, we also believe we have a responsibility to make Bitcoin's core software perform its core functions in the most efficient and reliable way possible: verifying and relaying blocks and transactions, thereby supporting Bitcoin's success as a decentralized digital currency. In terms of transaction relaying, Bitcoin Core may add some strategies, such as: Denial of Service (DoS) protection mechanism; fee evaluation strategy; but we will not block the relaying of transactions that have ongoing economic needs and can be reliably packaged into blocks."