> ## Documentation Index
> Fetch the complete documentation index at: https://docs.raydium.io/llms.txt
> Use this file to discover all available pages before exploring further.

# 2026-07-22 — AMM v4: remove OpenBook / Serum dependency

> AMM v4 removes its dormant OpenBook/Serum dependency, CPIs, and market-making instructions: v1 Swap/Deposit/Withdraw stay compatible, WithdrawPnl and SetParams are hard-breaking, and several instructions are no longer callable.

<Info>
  A documentation changelog entry. For the index of all updates, see [`reference/changelog`](/reference/changelog). For the protocol's own historical timeline, see [`introduction/history-and-milestones`](/introduction/history-and-milestones).
</Info>

AMM v4 **stopped sharing liquidity to OpenBook (formerly Serum) a long time ago**; the hybrid order-book market-making path has been dormant for years. This upgrade is the cleanup: it **removes the Serum dependency, all order-book CPIs, and the dead market-making instructions** from the program, leaving AMM v4 as a pure constant-product (`x·y=k`) AMM. It does **not** change any live trading behavior — there were no OpenBook orders left to stop placing.

## TL;DR for integrators

* **Swap / Deposit / Withdraw keep working without changes.** Transactions built with the old account layouts still execute — the removed Serum/market accounts are simply ignored (no validation, no CPI). `SwapBaseIn` / `SwapBaseOut` still expect **17 (+1 optional)** accounts; `Deposit` and `Withdraw` layouts are unchanged. You do **not** have to ship a client update to keep existing flows alive.
* **Migrate to the V2 swap entrypoints.** `SwapBaseInV2` / `SwapBaseOutV2` carry no market accounts and no `amm_open_orders` (8 accounts total), so transactions are smaller and cheaper. Routers/aggregators should route through V2.
* **`WithdrawPnl` is a hard breaking change (admin only).** It goes **17 (+1 optional) → 10** accounts with **no compatibility parsing**; the old layout misaligns (old #5 was `amm_open_orders`) and fails validation. Admin tooling must be updated.
* **`SetParams` is a hard breaking change (admin only).** Accounts shrink to `[amm, admin]`, and the `param` enum is **renumbered** (`Fees` 9 → 2, `SetOpenTime` 11 → 3); `AmmOwner`, `LastOrderDistance`, `UpdateOpenOrder` and the grid params are removed.
* **Several instructions are no longer callable.** `Initialize`, `PreInitialize`, `MonitorStep`, `MigrateToOpenBook`, `WithdrawSrm`, `SimulateInfo`, and `AdminCancelOrders` now revert. Use `Initialize2` to create pools.
* **On-chain account layouts are byte-stable, and error codes are unchanged.** `AmmInfo` / `StateData` keep their layout (old OpenBook fields retained but deprecated/frozen); the `AmmError` numbering is preserved, with only a new `NotAllowed` appended.

## Why this matters (for traders, LPs, and integrators)

* **Traders** see no change in swap behavior or pricing — the constant-product curve is unchanged. V2-layout swaps are cheaper to land because they carry \~8 fewer accounts.
* **LPs** keep the same deposit/withdraw economics. Liquidity has long sat entirely in the pool vaults, so pool value is fully on-pool; this upgrade only deletes the stale market plumbing.
* **Integrators** get smaller, simpler transactions and a quoting model that reads straight from the vaults. Existing integrations do not break (except admin `WithdrawPnl` / `SetParams`), but the v1-swap compatibility shim is temporary — migrate to V2 at your convenience.

## Instruction-level changes

### Still callable, layout unchanged (backward compatible)

`Initialize2`, `Deposit`, `Withdraw`, `SwapBaseIn`, `SwapBaseOut`, `CreateConfigAccount`, and `UpdateConfigAccount` keep their existing account lists. On `SwapBaseIn` / `SwapBaseOut`, `Deposit`, and `Withdraw` the OpenBook/market accounts are still accepted positionally but are **no longer validated or used** — no CPI is issued and pool reserves are computed vault-only. The account **count** must still match, so existing transactions continue to execute unchanged.

### `SwapBaseInV2` / `SwapBaseOutV2` — recommended path

Omit the market accounts and `amm_open_orders` entirely (8 accounts; tags 16 / 17). Quote math is identical to v1. New integrations and routers should use V2.

### `WithdrawPnl` — 17 (+1 optional) → 10 accounts (⚠️ hard breaking, no compatibility path)

`amm_open_orders` and all six market accounts are removed. The new fixed 10-account, admin-only layout has **no** compatibility parsing; the old layout misaligns and fails with errors such as `InvalidCoinVault`.

### `SetParams` — reduced to `[amm, admin]` (⚠️ hard breaking) + renumbered params

The authority, open-orders, target-orders, vault, and all market accounts are removed. The `param` enum is renumbered and trimmed:

| Param         | Old value | New value |
| ------------- | --------- | --------- |
| `Status`      | 0         | 0         |
| `State`       | 1         | 1         |
| `Fees`        | 9         | **2**     |
| `SetOpenTime` | 11        | **3**     |

All order-book-grid params (`OrderNum`, `Depth`, `AmountWave`, `MinPriceMultiplier`, `MaxPriceMultiplier`, `MinSize`, `VolMaxCutRatio`, `InitOrderDepth`, `SetSwitchTime`, `ClearOpenTime`, `Seperate`) plus `AmmOwner`, `LastOrderDistance`, and `UpdateOpenOrder` are removed. The `SetParamsInstruction` struct drops `new_pubkey` and `last_order_distance`.

### No longer callable (revert at runtime; builders removed)

| Instruction         | tag | Replacement                      |
| ------------------- | --- | -------------------------------- |
| `Initialize`        | 0   | `Initialize2`                    |
| `MonitorStep`       | 2   | none (order-book crank, retired) |
| `MigrateToOpenBook` | 5   | none                             |
| `WithdrawSrm`       | 8   | none (SRM fee discount, retired) |
| `PreInitialize`     | 10  | `Initialize2`                    |
| `SimulateInfo`      | 12  | off-chain / SDK quoting          |
| `AdminCancelOrders` | 13  | none                             |

## Reserve / state changes

* **Pool-asset formula.** Total pool assets are now `vault balances − pending PnL (need_take_pnl)`; the OpenBook open-order term — already zero in practice — is dropped. Quoting code can read straight from the vault balances.
* **Deprecated state fields.** `StateData.total_pnl_pc`, `total_pnl_coin`, `orderbook_to_init_time`, `swap_coin_in_amount`, `swap_pc_out_amount`, `swap_acc_pc_fee`, `swap_pc_in_amount`, `swap_coin_out_amount`, and `swap_acc_coin_fee` are retained for layout compatibility but **no longer updated**. Consumers relying on the `swap_*` volume counters should switch to trade logs.
* **`AmmInfo` init.** `coin_lot_size`, `pc_lot_size`, and `min_size` are now initialized to `0`.
* **Removed dependency and CPIs.** The `serum_dex` crate is dropped from `Cargo.toml`; all Serum DEX CPIs (`invoke_dex_new_order_v3`, `invoke_dex_cancel_order_v2`, `invoke_dex_settle_funds`, `invoke_dex_init_open_orders`, …) are removed from `invokers.rs`. Removed data structs: `LastOrderDistance`, `SimulateParams`, `RunCrankData`, `GetPoolData`, `GetSwapBaseInData`, `GetSwapBaseOutData`.