Intersect Freezes Dijkstra Phase 1 Scope With Linear Leios
Cardano’s first Dijkstra phase now has a defined technical scope covering Linear Leios, Nested Transactions and a broader package of ledger changes. The current objective remains delivery by the end of 2026, while Peras is reserved for Phase 2.
By SongMarketCap
Intersect has frozen the technical scope for the first phase of Cardano’s Dijkstra era following a July 29 presentation to the Technical Steering Committee.
The finalized package confirms Ouroboros Linear Leios and Nested Transactions alongside additional ledger, scripting and transaction changes. It turns the previously open Phase 1 roadmap into a defined implementation target for the next major Cardano protocol upgrade.
Dijkstra Phase 1 Scope Is Now Frozen
Intersect’s Upgrade Bulletin #28 states that “the hard fork scope for the first phase is now frozen” following the Technical Steering Committee presentation.
Phase 1 introduces the Dijkstra ledger era and Protocol Version 12.
Ouroboros Linear Leios, defined through CIP-164, is the headline scaling component. It extends Cardano’s existing Praos design with Ranking Blocks and Endorser Blocks, creating additional transaction processing capacity while preserving the underlying Praos security model.
Nested Transactions under CIP-118 are also included. The feature introduces child transactions with independent witnesses and execution contexts, enabling more flexible transaction structures for use cases such as multi-party coordination and fee sponsorship.
The frozen scope also covers Guard Scripts under CIP-112, account address enhancements through CIP-159, removal of the isValid transaction field under CIP-167, Non-segregated Block Body Serialization through CIP-176 and removal of the DRep delegation requirement for reward withdrawals under CIP-181.
Additional work includes the Plutus V4 script context, changes to reference input fees and reference script pricing, CIP-50 pledge leverage functionality and structural groundwork required for the later activation of Ouroboros Peras.
Linear Leios Changes Cardano’s Block Processing Model
Linear Leios is designed to increase the amount of transaction work Cardano can process without relying only on larger blocks or shorter slot intervals.
Cardano currently uses Praos blocks to carry transactions and advance the chain. Linear Leios adds Endorser Blocks alongside the regular Ranking Blocks.
Endorser Blocks can carry additional transaction data and are certified by stake-based committees. Their certificates can then be referenced by subsequent Ranking Blocks, allowing more transaction work to be processed while the main chain remains anchored to Praos.
Unlike earlier versions of the broader Leios design, Linear Leios does not use Input Blocks. The Dijkstra Phase 1 implementation centers on Ranking Blocks and Endorser Blocks.
Development is still active. Current work includes migration into the Dijkstra ledger era, conformance testing, block propagation, BLS-based certification and integration with Cardano node infrastructure.
Nested Transactions are further advanced, with ledger rules, serialization and supporting transaction structures already under implementation.
Neither feature is currently described as production-ready.
Linear Leios Changes Cardano’s Block Processing Model
Linear Leios is designed to increase the amount of transaction work Cardano can process without relying only on larger blocks or shorter slot intervals.
Cardano currently uses Praos blocks to carry transactions and advance the chain. Linear Leios adds Endorser Blocks alongside the regular Ranking Blocks.
Endorser Blocks can carry additional transaction data and are certified by stake-based committees. Their certificates can then be referenced by subsequent Ranking Blocks, allowing more transaction work to be processed while the main chain remains anchored to Praos.
Unlike earlier versions of the broader Leios design, Linear Leios does not use Input Blocks. The Dijkstra Phase 1 implementation centers on Ranking Blocks and Endorser Blocks.
Development is still active. Current work includes migration into the Dijkstra ledger era, conformance testing, block propagation, BLS-based certification and integration with Cardano node infrastructure.
Nested Transactions are further advanced, with ledger rules, serialization and supporting transaction structures already under implementation.
Neither feature is currently described as production-ready.