Forks are the splitting of the blockchain into two.
Usually, as a result of major protocol upgrade, a hard fork is created, and unintentional fork can be created due to bugs in the software.
When and Why Blockchain Networks Split
With the release of Homestead, due to major protocol upgrades, it resulted in a hard fork.
The protocol was upgraded at block number 1,150,000, resulting in the migration from the first version of Ethereum known as Frontier to the second version of Ethereum called Homestead.
The latest version is called Byzantium which is the first part of the Metropolis release.
An unintentional fork, which occurred on November 24, 2016, at 14:12:07 UTC was due to a bug in the Geth client’s journaling mechanism.
As a result, a network fork occurred at block number 2,686,351.
This bug resulted in Geth failing to prevent empty account deletions in the case of the empty out-of-gas exception.
Why This Matters for Blockchain Technology
This was not an issue in Parity (another popular Ethereum client).
This means that from block number 2,686,351, the Ethereum blockchain is split into two, one running with the Parity clients and the other with Geth.
This issue was resolved with the release of Geth version 1.5.3.
As a result of the DAO hack, the Ethereum blockchain was also forked to recover from the attack.
Key Points to Remember
- Forks in the blockchain Forks are the splitting of the blockchain into two.
- Usually, as a result of major protocol upgrade, a hard fork is created, and unintentional fork can be created due to bugs in the software.
- With the release of Homestead, due to major protocol upgrades, it resulted in a hard fork.
- The protocol was upgraded at block number 1,150,000, resulting in the migration from the first version of Ethereum known as Frontier to the second version of Ethereum called Homestead.
Going Deeper: Advanced Concepts
Forks in the blockchain Forks are the splitting of the blockchain into two. This can be intentional or non-intentional. Usually, as a result of major protocol upgrade, a hard fork is created, and unintentional fork can be created due to bugs in the software. With the release of Homestead, due to major protocol upgrades, it resulted in a hard fork. The protocol was upgraded at block number 1,150,000, resulting in the migration from the first version of Ethereum known as Frontier to the second version of Ethereum called Homestead. The latest version is called Byzantium which is the first part of the Metropolis release. This was released as a hard fork at block number 4,370,000. An unintentional fork, which occurred on November 24, 2016, at 14:12:07 UTC was due to a bug in the Geth client’s journaling mechanism. As a result, a network fork occurred at block number 2,686,351. This bug resulted in Geth failing to prevent empty account deletions in the case of the empty out-of-gas exception. This was not an issue in Parity (another popular Ethereum client). This means that from block number 2,686,351, the Ethereum blockchain is split into two, one running with the Parity clients and the other with Geth. This issue was resolved with the release of Geth version 1.5.3. As a result of the DAO hack, the Ethereum blockchain was also forked to recover from the attack. This was discussed in , Smart Contracts.
Conclusion
Forks in the blockchain represents one of the many innovative layers that make blockchain technology so powerful and transformative. As distributed systems continue to evolve, a solid understanding of these core concepts becomes increasingly valuable — not just for developers, but for anyone building, investing in, or working alongside blockchain-powered systems.
Whether you are just starting your blockchain journey or deepening existing expertise, mastering these fundamentals gives you the tools to think clearly about decentralized systems and make smarter decisions in this rapidly evolving space.