What are Cardano hard forks?
Here you will learn what Shelley, Allegra and Mary mean and what these Cardano hard forks are all about. ()
The Cardano blockchain runs on thousands of independent nodes. They all use an up-to-date software version so that they can exchange data reliably.
Most importantly, it’s about finding the consensus on block production. On average, a new block is created every 20 seconds. All nodes must receive this and check for validity before the next block can be placed on it.
Blockchains are constantly evolving and getting new features. This means that all these nodes need to be updated by the stake pool operators. This is relatively common, especially with Cardano, as many new features such as token locking, smart contracts, and governance are gradually added. For good reason, Cardano has played a leading role in statistical comparisons of developer activity for years.
get better step by step
In the case of minor updates and function enhancements, this is done in an uncomplicated and continuous manner. The old and new versions remain compatible. The normal user does not notice any of this.
But when it comes to fundamental protocol changes, blockchains perform what is known as a hard fork. In this case, a new software version is used which brings incompatible functions, a new data format or changed communication to the old version.
With earlier blockchain generations, a hard fork took place in which all operators (miners) convinced of the innovation started their nodes with the new version at a certain time announced in advance. The others stayed with the old version. Often this ended up in two separate blockchains. A well-known example is the Ethereum DAO hardfork of 2016 from which ETH and ETC emerged. Or in 2017, the Bitcoin Cash hardfork where no agreement could be found on the maximum block size and implementation of Segwit.
Cardano has also provided innovations in this area. The so-called Hardfork combinator technology allows a smooth and therefore controlled and secure transition from an old to a new protocol version. In this process, the proportion of blocks that are generated according to the old specification is gradually reduced over several epochs and replaced by new blocks. So the transition from the Byron era to the Shelley era started in August 2020 and was migrated in a slow, controlled way over several months.
However, an update can also take place from one epoch to the next. To do this, the nodes install the new software, which can handle both the old and new protocol versions. A proposal for the time of the changeover is then submitted at the protocol level, which serves as a common signal to all nodes for the changeover to the new version. So there will be no rebooting or splitting of the blockchain.
Not every software update means a hard fork event. In order to clearly identify the various hard forks, names are given to the respective era introduced, such as
- Shelley (Aug-2020) : switch from BFT to Ouroboros PoS.
- Allegra (Dec 2020) : Introduction of token locking
- Mary (Feb 2021) : Actuation of multi assetsupport.
So from the risky and uncertain hard forks of the early blockchain generation, Cardano has become what can be called a decentralized yet coordinated software update.