Protocol T024

Protocol T024#

This page lists the changes brought by protocol T024 with respect to Seoul (see Protocol naming). For the list of changes brought by Seoul with respect to Rio, see Protocol Seoul.

For a higher-level overview of the most salient new features see the announcement blog.

The code can be found in directory src/proto_024_PsU87LFi of the master branch of Octez and the full documentation in this page.

Environment Version#

Protocol t024 uses the same environment version V15 as protocol Seoul.

Smart Rollups#

Data Availability Layer#

Adaptive Issuance#

Michelson#

  • Added a new instruction INDEX_ADDRESS. It provides a unique identifier of type nat for values of type address, stored in the context. (MRs !18866, !18943)

  • Added a new instruction GET_ADDRESS_INDEX. It returns the unique identifier of type nat option for values of type address, if the address has already been indexed through INDEX_ADDRESS; it returns None otherwise. (MR !18866)

Gas improvements#

RPC Changes#

  • Breaking change Updated RPC GET /chains/<chain_id>/blocks/<block_id>/helpers/validators to group delegates by level. The returned list contains one element for each queried level (by default, only the current level), and contains four fields: the level itself, the consensus_threshold required for the current level, the consensus_committee of the current level, and delegates which is the list of validators for that level. Each element of this last list contains the fields present in the previous version of this RPC: delegate, “slots” which have been renamed to rounds, consensus_key, and companion_key (optional). Also include new fields for delegates, attesting_power, with their attesting power for the level, and attestation_slot, their slot for the given level. (MRs !18931, !18959, !18984)

  • Breaking change Updated RPC GET /chains/<chain_id>/blocks/<block_id>/context/issuance/expected_issuance. Output field baking_reward_bonus_per_slot has been replaced with baking_reward_bonus_per_block, and attesting_reward_per_slot with attesting_reward_per_block. Their respective values are consequently 7000 times as high as before (since there are 7000 slots per block). (MR !18959)

  • Added a new RPC GET /chains/<chain_id>/blocks/<block_id>/helpers/stake_info. It returns the baking power distribution for all the active delegates at the current cycle. (MR !18019)

  • Added a new RPC GET /chains/<chain_id>/blocks/<block_id>/helpers/tz4_staker_number_ratio?cycle=<cycle>. It returns the portion of active delegates that sign with a BLS key. The cycle argument, if omitted, defaults to the current cycle. (MR !19093)

  • Added a new RPC GET /chains/<chain_id>/blocks/<block_id>/context/destination/<destination>/index. It returns the index of the given destination (e.g. tz1, Smart Rollup addresses, etc.), or null if the destination has not been indexed by the opcode INDEX_ADDRESS yet. (MR !18944)

Blocks and block receipts#

  • Breaking change Removed obsolete field adaptive_issuance_vote from the block header, and fields adaptive_issuance_vote_ema and adaptive_issuance_activation_cycle from the block metadata. Note that the adaptive issuance activation cycle (which is 748 on mainnet) can still be queried via the RPC GET /chains/<chain>/blocks/<block>/context/adaptive_issuance_launch_cycle. (MR !19215)

Operation receipts#

  • Added a new field address_registry_diff to the operation metadata. It contains the addresses that have been newly indexed through the opcode INDEX_ADDRESS. (MR !18870)

Errors#

Protocol parameters#

6s Block Time (MRs !19045, !19473)#

Breaking change Block time has been reduced from 8 seconds to 6 seconds on mainnet (on ghostnet, it remains unchanged at 4 seconds). That is, a block can be produced with a delay of 6 seconds with respect to the previous block, if the latter is at round 0.

This reduced block time comes with the updates of multiple related protocol parameters:

Changes to protocol parameters#

Parameter (unit)

Old (seoul) value

New value

minimal_block_delay (seconds)

8

6

delay_increment_per_round (seconds)

4

3

blocks_per_cycle (blocks)

10800

14400

blocks_per_commitment (blocks)

84

112

nonce_revelation_threshold (blocks)

300

400

max_operations_time_to_live (blocks)

450

600

hard_gas_limit_per_block (gas unit)

1386666

1040000

Smart rollup protocol parameters have also been updated accordingly, in order to preserve the same durations as in the previous protocol. For example, the challenge window is still two weeks.

Changes to smart rollup protocol parameters#

Parameter (unit)

Old (seoul) value

New value

smart_rollup_challenge_window_in_blocks

151200

201600

smart_rollup_commitment_period_in_blocks

112

150

smart_rollup_max_lookahead_in_blocks

324000

432000

smart_rollup_timeout_period_in_blocks

75600

100800

Note that the smart_rollup_max_active_outbox_levels has not been updated, because the current storage implementation of the executed outbox message in the Layer 1 does not allow for a safe update. As a consequence, the maximal allowed period of withdrawal has been reduced from ~14 days to ~10 days.

Feature flags#

  • Replaced the feature-controlling parameter all_bakers_attest_activation_level with all_bakers_attest_activation_threshold. This causes all-bakers-attest to activate as soon as the ratio of bakers that use a tz4 consensus keys exceeds the specified threshold, set to 50% in protocol t024. (MR !19093)

Bug Fixes#

  • Breaking change Updated cache functions to include the context when needed. Previously backtracked gas costs for some cache calls are now properly accounted for, increasing by at most 2 units of gas per function call. (MR !19134)

Minor Changes#

Internal#

  • When activating this protocol directly from Genesis (so only in tests and on some test networks):

    • Baking rights of bootstrap accounts for the first few cycles are now computed with Adaptive Issuance enabled, meaning that delegated tez are already weighted less than staked tez. (MR !16945)

    • Fixed registration of bootstrap accounts with an initial consensus key. (MR !19314)

  • Removed dead code related to Adaptive Issuance activation, EMA, and per-block vote. (MRs !15789, !19215)