Agave 4.2: The Migration Checklist

---
name: agave-42-readiness
description: Audit this repository for Solana Agave 4.2 breaking changes. Use when asked to check Agave 4.2 readiness, migrate for transaction v1, or audit Solana RPC/streaming integration code.
---

# Agave 4.2 Readiness Audit

Audit the repository for the five Agave 4.2 breaking changes below. For each, locate the relevant code, judge whether it is affected, and report file:line with a verdict of PASS, FAIL, or NEEDS REVIEW. Do not modify code unless asked to fix findings.

## Check 1: Transaction v1 opt-in (highest priority)
Find every `getBlock`, `getTransaction`, and `getTransactionsForAddress` (with `transactionDetails = full`) call. Search all languages, raw JSON-RPC request bodies (`"method": "getBlock"`), and SDK wrappers (`connection.getBlock`, `connection.getParsedTransaction`, `rpc_client.get_block`, `client.GetTransaction`, and similar).
- FAIL if `maxSupportedTransactionVersion` is absent or set to 0. Once the v1 feature gate activates, these calls fail on v1 transactions with JSON-RPC error code -32015: `"Transaction version (1) is not supported by the requesting client. Please use \"maxSupportedTransactionVersion\" in your request."` Also grep for `-32015` in logs and error handlers; hits mean the project has already been failing on versioned transactions.
- Also FAIL if the project deserializes raw transaction bytes (custom indexer, signer, relayer) and the decoder does not handle the v1 layout: version byte 0x81 (decimal 129, vs 0x80 for v0), signatures at the END of the transaction instead of the front, compute budget carried in a header config mask instead of instructions.
- Correct fix order: upgrade the Solana SDK to a v1-capable version (JS: @solana/kit 8.0+ or @solana/web3.js v3), then set `maxSupportedTransactionVersion: 1`. Flag if the parameter is set but the installed SDK version predates v1 support.
- Also FAIL if priority fee or compute budget extraction scans for ComputeBudget program instructions (`ComputeBudget111111111111111111111111111111`, `setComputeUnitPrice`, `setComputeUnitLimit`). A v1 transaction contains no such instructions; its values live in a `transactionConfig` object in the message. Scanning code reads every v1 transaction as paying zero priority fee.
- Units trap, FAIL even when the code reads `transactionConfig`: legacy/v0 `setComputeUnitPrice` is **micro-lamports per compute unit**; v1 `priorityFee` is a **total in lamports**. Code that ports the old `price × computeUnitLimit ÷ 1e6` math onto the new field misreports fees. `priorityFee` needs no multiplication. Null fields mean the sender did not set them.

Example v1 message:
```
"message": {
  "instructions": ["… no ComputeBudget instruction here …"],
  "recentBlockhash": "...",
  "transactionConfig": {
    "computeUnitLimit": 200000,
    "heapSize": null,
    "loadedAccountsDataSizeLimit": 200000,
    "priorityFee": 50000
  }
}
```
`"priorityFee": 50000` = this transaction pays 50,000 lamports total. Legacy and v0 messages omit `transactionConfig` entirely, so its presence (or `"version": 1` on the enclosing transaction) identifies v1.

## Check 2: rewardType parsed as a closed enum
Find code reading `rewardType` from `getBlock`, `blockSubscribe`, or Geyser/gRPC reward arrays. Search for the existing values too (`"Fee"`, `"Rent"`, `"Staking"`, `"Voting"` in JSON paths; `RewardType::` in Rust; reward-type enums in generated gRPC code).
- 4.2 adds the value `DeactivatedStake` — same capitalized casing as the existing JSON values (`"Staking"`, not `"staking"`). A reward entry looks like:
```
{
  "pubkey": "...",
  "lamports": 10000000,
  "postBalance": 50000000000,
  "rewardType": "DeactivatedStake",
  "commission": null
}
```
- FAIL if unknown values throw, or fall into a match/switch arm or if/else chain that drops the record without logging: a Rust `match` without a logging wildcard arm, a TS `switch` whose `default` is silent, a lookup table where a missing key skips the entry. Closed parsers lose every deactivating stake account's final payout with no error.
- FAIL if a deserialization enum (serde, protobuf mapping, Zod/io-ts schema) rejects unknown reward-type strings; the whole reward array or block record errors out, not just one entry.
- PASS requires unknown values to be preserved or logged. If the project aggregates staking yield by filtering `rewardType == "Staking"`, add a NEEDS REVIEW noting the team must decide whether `DeactivatedStake` payouts belong in totals; they are final payouts, not recurring yield.

## Check 3: Transaction-to-account-update matching
Find logic that correlates transactions with account update notifications. Search for `accountSubscribe`, Yellowstone/LaserStream `SubscribeRequest` account filters, and code that builds a pending set of a transaction's writable accounts and waits to check them off as updates arrive.
- FAIL if it assumes every writable account in a transaction produces an update. On 4.2, an account that was write-locked but not modified emits nothing; logic awaiting the full set hangs forever. Typical patterns: a countdown/completion latch over `message.accountKeys` writable entries, a timeout that treats a missing update as an error, a reconciler that re-fetches "late" accounts. The fee payer is the only account guaranteed to update.
- The correct interpretation of a missing update is "this account did not change"; its pre-transaction state is still current.
- Also FAIL liveness or health checks that treat update frequency as a signal, and flag alert thresholds calibrated to pre-4.2 volume; account-subscription event counts drop roughly 80% on 4.2.

## Check 4: Token-2022 jsonParsed changes
Find parsers reading Token-2022 `jsonParsed` output: instruction types `depositConfidentialTransfer` and `withdrawConfidentialTransfer`, and mint-account `extensions` arrays.
- FAIL if confidential-transfer parsers read `source` or `destination`; 4.2 replaces both with a single `account` field. New shape:
```
"info": {
  "account": "...",   // was source + destination
  "mint": "...",
  "amount": 42,
  "decimals": 9,
  "owner": "..."      // multisig: "multisigOwner" + "signers" array instead
}
```
- New instruction types now come back parsed instead of raw: `unwrapLamports`, `confidentialBurn`, permissioned burn, and batch operations. FAIL if code assumes these arrive as raw base64/base58 data, and flag `unwrapLamports` parsers that require `info.amount` or treat it as a number: it is a **string** and is **omitted entirely** when the instruction unwraps the full balance.
- Extensions array: on 4.1, one unrecognized extension type on a mint made the node return `"extensions": []`, hiding every extension including known ones. On 4.2 the full array returns, each entry as `{"extension": "<name>", "state": {...}}`, with still-undecodable ones as `{"extension": "unparseableExtension"}`. FAIL if code treats an empty array as proof of no extensions, or throws on extension names it does not recognize (`scaledUiAmountConfig`, `pausableConfig`, `permissionedBurnConfig`, `unparseableExtension`, and future values).

## Check 5: Slot timing and streaming dependencies
- FAIL on hardcoded slot-duration constants: `400`, `0.4`, `400_000` microseconds, `MS_PER_SLOT`, `SLOT_DURATION`, `DEFAULT_MS_PER_SLOT`, or slot-to-time math like `slots * 400`. Mainnet is 350ms, cutting to 300ms on Aug 28, 2026, stepping toward 200ms. Constants inherited from an SDK count as hardcoded. PASS requires timing derived from block timestamps (e.g. `getBlockTime` deltas over a few thousand slots) or a config value with a documented update path.
- Also flag capacity assumptions keyed to block rate: batch sizes, poll intervals, and queue depths sized for 400ms blocks fall behind as slots shorten.
- In Cargo.toml/Cargo.lock: FAIL if `yellowstone-grpc-client` < 13.3.0 or `yellowstone-grpc-proto` < 12.6.0 (first proto carrying transaction v1). Recommend client 13.3.0, proto 12.6.0, both declared.
- For Go gRPC clients: flag if generated protos predate transaction v1; regenerate from latest Yellowstone protos and solana-storage-proto.
- If the project uses the Helius LaserStream SDK (package names `helius-laserstream`, `laserstream` in dependencies): FAIL if below JS 0.8.4, Rust 0.6.3, or Go 0.2.0 (first releases with the v1-capable proto).

## Report format
Output a table: check, verdict, file:line references, one-line remediation. End with an overall verdict (READY / NOT READY) and the ordered fix list. Full migration guide: https://www.helius.dev/blog/agave-4-2-migration-checklist