Cryptocurrency upgrades typically involve modifications to the underlying software or protocol that governs a specific blockchain network. These upgrades can lead to the introduction of new features, adjustments in consensus mechanisms, or modifications designed to improve security protocols. An upgrade may require a hard fork or a soft fork, depending on whether the changes are backward-compatible or not. Hard forks lead to a split in the blockchain, creating a new version of the cryptocurrency, while soft forks do not lead to such a split. Notable examples of cryptocurrency upgrades include the Ethereum network's transition from Proof of Work to Proof of Stake (the Ethereum 2.0 upgrade) and Bitcoin’s implementation of Segregated Witness (SegWit).