Changelog

A running log of the changes that move user-visible SDK or on-chain behaviour. Internal refactors and perf work are summarised when they affect CU budgets or account sizes.

2026-04-20 — Phase 2.1 & API unification

Breaking

• Mode 0 dropped. The Secp256r1 auth path now only supports raw clientDataJSON from a real browser authenticator. Secp256r1Signer.sign() must return clientDataJson; the typeAndFlags parameter of buildAuthPayload is gone. Bot / programmatic signing should use Ed25519 authorities instead.
• Authority account layout changed. Secp256r1 authorities now store rpIdHash (32 bytes) instead of the variable-length rpId string. Account size is fixed at 145 bytes (Ed25519 authorities stay at ~80 bytes). Instruction data for CreateWallet / AddAuthority / TransferOwnership is unchanged — clients still send rpId; the program hashes it once at write time.
• Unified prepare/finalize API. Every Secp256r1 op now has a matching client.prepare* / client.finalize* pair — prepareExecute/finalizeExecute, prepareCreateSession/finalizeCreateSession, etc. The old *Prepare methods that returned an embedded finalize closure are gone.
• Fee model. Protocol fee is now charged on every transaction when the protocol is enabled — not opt-in per fee_payer. Registering a FeeRecord is opt-in for reward tracking; unregistered payers still pay the fee but don't accumulate a claim at token launch.

Improvements

• CU reductions. Execute Secp256r1: 10,883 → 9,495 CU (-12.8%). Execute Session: 4,723 → 4,105 CU (-13.1%). Zero-copy compact instructions + elimination of Vec concats in the hot path.
• publicKeyBytes auto-fetch. Secp256r1Params.publicKeyBytes is now optional — the client reads the pubkey off the on-chain Authority account via the new readAuthorityPubkey helper. Integrators only need to persist credentialIdHash per user.
• Serializable DeferredPayload. New serializeDeferredPayload() / deserializeDeferredPayload() helpers turn a payload into JSON-safe bytes. Unblocks cross-machine deferred flows (sign TX1 on the user's device, submit TX2 from a server relayer).

Security hardening

• H1 — vault / token invariants enforced around CPIs in session+actions execute (prevents round-trip swap bypass of SolMaxPerTx).
• H2 — admin paths require program-owned ProtocolConfig and TreasuryShard accounts (prevents account-spoofing on withdraw / update).
• M1 — clientDataJSON parser correctly skips strings nested inside objects.
• payer and adminAuthority metas switched to writable where required for rent refunds.

What to do

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Earlier milestones

• Solita artifacts removed. The SDK is now fully hand-written for fine-grained control over wire layout. No IDL-generated wrappers remain.
• Protocol fee system live on mainnet. Sharded treasury (16 shards by default), per-fee_payer FeeRecord counters, fees collected in native SOL.
• Seedless + session.money launched. First production integrators running on the LazorKit execution layer.

For the authoritative change history, browse the lazorkit-protocol git log.