It is the ninth Tezos protocol upgrade and was jointly developed by Nomadic Labs, Marigold, TriliTech, Oxhead Alpha, Tarides, DaiLambda, Functori & Tweag.
Ithaca 2 introduces Tenderbake, a new consensus algorithm for Tezos. A comprehensive introduction can be found here, but the headlines are:
- Fast, deterministic finality: A block can be trusted to be final after two blocks, regardless of delays in network communication. Under normal circumstances this is one minute.
- Choosing a safe network over a live network: As long as 2/3 of the stake is honest, Tenderbake allows no parallel block production that can potentially revert transactions. Any small fork stops producing blocks, and if more than 1/3 of the total stake is isolated, the entire network will halt and await reconnection.
- The road to faster blocks: While block time is kept at 30 seconds in Ithaca 2, Tenderbake makes it safe to introduce lower block times in future protocol upgrades.
A number of other changes are mostly relevant for bakers:
- Lower minimum stake: The minimum amount of tez required to receive baking/endorsement rights is reduced from 8,000 to 6,000.
- Instant rewards: Baking/endorsement rewards will no longer be frozen for 5 cycles as has been the case up until now.
- Fewer problems with overdelegation: Instead of making a deposit with each baked/endorsed block, bakers freeze 10% of their stake upfront in each cycle. Bakers can set a limit for how much of their stake will be used. This prevents missed slots from overdelegation.
- Total stake is used: Rolls are no longer used for assigning baking/endorsement rights. Bakers will receive slots in proportion to their actual stake, which should benefit small bakers in particular.
- More endorsements, steady participation: Endorsement slots per block are increased from 256 to 7,000. This means a baker with the minimum amount of tokens will participate every 10 blocks on average.
Also included in Ithaca 2
Precheck of manager operations: The new version of the protocol allows any Tezos shell (e.g., Octez and TezEdge) to avoid fully executing manager operations (those created by end users, e.g. transfers and smart contract calls) before gossiping them through the network. This lets operations reach bakers faster, and is a prequel to further optimizations that can increase throughput.
Liquidity Baking: Ithaca 2 includes an increase to the liquidity baking sunset level of 819,200 blocks, or twenty voting periods, roughly an additional ten months. To balance this increase, the threshold for activating the escape hatch is lowered from 50% to 33%.
… and more: We invite you to look at the changelog for a full description of the contents of Ithaca 2, which includes a new environment version (V4), updates to Michelson, as well as minor changes and bug fixes.
Congratulations to everyone involved in the development of this protocol amendment and welcome to the Tezos blockchain, Ithaca 2!
A special thank you to the Tezos community for updating nodes, bakers, signer software/hardware, indexers, etc., in preparation for Tenderbake – and for reaching out to others to make sure everyone was ready.
Our next protocol proposal, “J”, is targeted for injection in mid-April. It will be the first of a series of scaling-focused upgrade proposals meant to prepare Tezos for high-throughput use cases and long-term growth. Stay tuned!