Polymarket V2 Migration

Cutover: April 28, 2026 at ~11:00 UTC. After this moment, V1 orders are rejected and V2 orders settle in pUSD (a 1:1 backed wrapper around USDC.e) instead of USDC.e directly. Your funds are safe — USDC.e is convertible to pUSD indefinitely, and there is no deadline to migrate. Migration takes one click on your Simmer dashboard when you want to trade Polymarket again.

Your Deposit Wallet is a smart contract on Polygon. Do not deposit funds from other chains, or other assets on Polygon except for USDC.e or pUSD — they will be unrecoverable.This includes native POL: do not send POL to your Deposit Wallet. V2 trades are gasless via Polymarket’s relayer, so the Deposit Wallet doesn’t need POL — and POL sent to it cannot be moved out.If you need POL for gas (one-time, for the V1 → V2 wrap), send it to your agent wallet — the EOA Simmer signs trades from — not your Deposit Wallet.

TL;DR

What’s changing. Polymarket is upgrading its exchange on April 28, 2026. V2 uses pUSD instead of USDC.e as the collateral token. Every pUSD is backed 1:1 by USDC.e.
What’s the same. Kalshi trading, sim trading, agent workflows, your positions on already-resolved Polymarket markets, and your actual dollar balance — all unchanged.
What you need to do. If you hold USDC.e in your Simmer Polymarket wallet, follow the dashboard migration before your next Polymarket trade. It converts USDC.e to pUSD, moves you onto a Deposit Wallet when needed, and activates V2 trading.
No deadline. USDC.e doesn’t expire. Migrate when you’re ready to trade. Your funds sit safely in USDC.e in the meantime.

What’s happening on April 28

At approximately 11:00 UTC on April 28, 2026, Polymarket turns off V1 and turns on V2 at the same production URL. From that moment:

Action	Before cutover	After cutover
Polymarket order	V1 struct, settles in USDC.e	V2 struct, settles in pUSD
Order with V1 struct	✅ Accepted	❌ Rejected with `order_version_mismatch`
Redeeming a resolved position	Pays out USDC.e	Pays out pUSD
Funds in your wallet	USDC.e ↔ pUSD both spendable on Polymarket	Only pUSD spendable; USDC.e still on-chain but inert for trading
USDC.e → pUSD conversion	Available via Collateral Onramp	Available via Collateral Onramp (unchanged)

V1 orders still resting in the order book at cutover are cleared by Polymarket. If you have open Polymarket orders on the eve of April 28, cancel them first or accept that they’ll be wiped.

What you need to do

The flow depends on your wallet type. Most users have a managed wallet (default — Simmer creates and manages the trading wallet for you). If you set up an external wallet (self-custody) instead, the flow is similar but you sign the transactions in your browser wallet. The dashboard walks you through the applicable steps. For active V2 trading, the normal path is:

Wrap USDC.e → pUSD (1:1, no fee — pUSD is the V2 collateral token)
Use a Deposit Wallet — Polymarket V2 routes trades through a per-user smart contract that holds collateral and submits gasless trade batches
Activate V2 trading by approving the V2 exchange contracts to spend pUSD + transfer outcome tokens (V2 has new spender addresses; V1 approvals don’t carry over)

If your account already has a Deposit Wallet, the dashboard skips the upgrade step and uses it. If your account still trades directly from an older EOA, the dashboard shows “Upgrade to deposit wallet” between wrap and approvals. The upgrade deploys the smart contract on your behalf (managed wallet) or prompts a browser signature (external wallet). No funds leave your control during the upgrade. You should not treat the Deposit Wallet upgrade as a rare recovery path. It is the default V2 destination for new managed users and the standard migration target for external users. Without a Deposit Wallet, older EOAs may receive maker address not allowed rejections from the Polymarket CLOB.

Managed wallet (default for most users)

This is the path for anyone who hasn’t explicitly set up an external wallet on Simmer.

Go to your Agent dashboard → Portfolio → Polymarket tab
Click the orange “Migrate to V2” banner
Wait ~1–2 minutes — Simmer signs and submits the required on-chain transactions on your behalf:
- 1 USDC.e approve (so the Onramp can pull it)
- 1 wrap (USDC.e → pUSD)
- 1 Deposit Wallet deployment or activation step, if your account does not already have one
- 5 pUSD approvals (4 trading spenders + 1 V2 Fee Escrow)
- 6 ERC-1155 setApprovalForAll (4 trading spenders + 2 redemption adapters)
No wallet popups, no extra clicks.
Deposit Wallet ready. Once deployed, the Deposit Wallet becomes your V2 trading address; funds move there automatically and V2 approvals apply to it. Accounts that already have a Deposit Wallet continue using the existing one.
The banner turns green — “Migrated to V2 — ready to trade”
Your balance updates — USDC.e drops to $0, pUSD appears with your migrated amount

The migration’s approve + wrap + V2 approvals are gas-paid from your agent wallet (the EOA Simmer signs trades from — not your Deposit Wallet). Plan for ~0.5 POL on the agent wallet before you click Migrate. The dashboard shows the agent wallet address for top-up. Do not send POL to your Deposit Wallet — it will be permanently stuck. If you migrated under the old wrap-only flow (before April 28 evening), your USDC.e is now pUSD but the V2 trading approvals weren’t set. The banner re-appears as “Polymarket V2 — activate trading” with a single button to set the V2 approvals.

External wallet (self-custody — MetaMask, Rabby, Coinbase Wallet, etc.)

Works on both desktop (browser extensions) and mobile (WalletConnect / in-app wallet browsers). Stage 1 — Wrap USDC.e to pUSD:

Go to your Agent dashboard → Portfolio → Polymarket tab
Make sure your trading wallet is the active account — this may differ from the wallet you used to log in to Simmer:
- Desktop: switch the active account in your browser wallet extension (MetaMask, Rabby, etc.)
- Mobile: connect via WalletConnect or open Simmer inside your wallet’s in-app browser, with the trading wallet selected
Click the orange “Migrate to V2” banner
Sign 2 transactions in your wallet — approve USDC.e for the wrap contract, then wrap USDC.e → pUSD

Stage 2 — Deposit Wallet:

If the banner shows an “Upgrade to deposit wallet” step, click “Upgrade” and sign the deploy transaction in your wallet. This deploys your personal Deposit Wallet smart contract on Polygon. If you already have a Deposit Wallet, the dashboard skips this step and uses the existing one. Once deployed, all V2 trades route through your Deposit Wallet.

Stage 3 — Activate V2 trading:

The banner switches to “Activate V2 trading” with an approval checklist
Click “Activate Trading” and sign ~11 more transactions:
- 5 pUSD approvals (4 trading spenders + 1 V2 Fee Escrow)
- 6 setApprovalForAll on the ConditionalTokens contract (4 trading spenders + 2 redemption adapters)
The banner turns green — “Migrated to V2 — ready to trade”

Total: ~13–14 wallet signatures, depending on whether the dashboard needs to deploy your Deposit Wallet, ~1–2 minutes including transaction confirmations. Your agent wallet (the EOA — not the Deposit Wallet) needs at least 0.5 POL for gas across all transactions. If you migrated under the old wrap-only flow, your wallet has pUSD but the V2 approvals weren’t set. The banner re-appears as “Polymarket V2 — activate trading” — click it to render the approval checklist for Stage 3.

You can migrate any time — before cutover, at cutover, or weeks later. No deadline. Your USDC.e is safe regardless.

If your Polymarket wallet holds no USDC.e

Nothing to do. If you deposit fresh USDC.e later, the dashboard will prompt you to migrate when you try to trade.

If you use Kalshi or sim trading only

Nothing changes. Kalshi trading is independent of Polymarket. Sim trading is independent of every external venue. This migration is Polymarket-only.

Timeline

April 25-27, 2026 — Pre-cutover window

V1 is still live. The Simmer dashboard “Migrate to V2” banner has not yet appeared — it activates after Simmer enables V2 routing on April 28 (see next step). External-wallet users can optionally pre-migrate via polymarket.com’s gasless wrap flow today. Two things worth doing now: (1) if you have open Polymarket V1 limit orders, cancel them — the V1 order book gets wiped at cutover; (2) make sure your Polymarket wallet has at least 0.1 POL for migration gas (applies to both managed and external wallets — see “Do I need POL” FAQ below).

April 28, 2026 ~11:00 UTC — Cutover

Polymarket flips the switch. V1 is retired. V2 takes over the production URL. Simmer pauses Polymarket order placement briefly during the window (Kalshi and sim trading continue).

April 28, 2026 ~12:05 UTC — V2 trading live on Simmer

Simmer enables V2 order routing. The dashboard “Migrate to V2” banner activates for users still holding USDC.e — one click migrates to pUSD. The wrap is user-triggered (no background cron): managed-wallet users click the banner and Simmer signs the on-chain approve + wrap from their managed key (gas paid from the wallet’s POL balance); external-wallet users click the banner and sign the same transactions in their connected browser wallet.

Ongoing

USDC.e can be wrapped to pUSD at any time via the Simmer dashboard or directly via polymarket.com. No deadline, no expiration.

What if I don’t migrate?

Your USDC.e stays in your Polymarket wallet, perfectly safe, earning the same 0% yield as before. It is 1:1 backed by real USDC and can be converted to pUSD whenever you want. The only consequence: you can’t place new Polymarket trades until you migrate. Kalshi and sim venues are unaffected. You can also always withdraw your USDC.e back to your personal wallet via the dashboard’s Withdraw button.

FAQ

Is my USDC.e safe after April 28?

Yes. USDC.e is not going anywhere. It’s still a valid ERC-20 token on Polygon, 1:1 redeemable for real USDC. V2 just uses a different token (pUSD) for Polymarket order settlement. Your USDC.e balance keeps working for everything USDC.e has always worked for — withdrawals, bridges, other DEXes.

What is pUSD exactly?

pUSD (PolyUSD) is an ERC-20 token at 0xc011a7e12a19f7b1f670d46f03b03f3342e82dfb on Polygon. Every pUSD is backed 1:1 by USDC.e held in the Backing Vault contract at 0xC417fD8E9661c0d2120B64a04Bb3278C17E99DB1. You can mint pUSD by depositing USDC.e via the Collateral Onramp and burn pUSD to withdraw USDC.e via the Collateral Offramp. The conversion rate is always 1:1.

Will I lose any money in the migration?

No. The migration is a 1:1 token swap with no fees beyond the Polygon gas cost for the approve + wrap transactions (~0.06 POL worst case, roughly $0.02). Simmer and Polymarket take no cut. We recommend keeping at least 0.1 POL in your wallet to cover the migration plus a buffer for any retries.

Do I need POL (gas) to migrate?

Yes — the wrap requires an approve + wrap transaction pair, both paid in POL on Polygon. This applies to both managed and external wallets — Simmer signs the transactions on your behalf for managed wallets, but the gas still comes out of your agent wallet’s POL balance (the EOA Simmer signs trades from — not your Deposit Wallet). The dashboard pre-flight requires at least 0.1 POL before letting you click Migrate. If you don’t have enough, the dashboard will display your agent wallet address so you can send POL from an exchange before retrying.Important: do not send POL to your Deposit Wallet. The Deposit Wallet has no native-asset withdrawal path — POL sent there cannot be moved out. POL only belongs on the agent wallet (EOA) for one-time migration gas. After migration, V2 trades are gasless via Polymarket’s relayer.

What happens if I send funds to my Deposit Wallet on the wrong network or in the wrong asset?

Your Deposit Wallet is a smart contract that only exists on Polygon. The same address on Base, Ethereum, Arbitrum, or any other chain is empty space, not your wallet — funds sent there cannot be recovered.On Polygon itself, the Deposit Wallet only has withdrawal paths for USDC.e and pUSD. Native POL, ETH, or arbitrary tokens sent to it cannot be moved out by you or by Simmer.If this happens, contact support — we’ll confirm what the on-chain situation is, but in most cases the funds are unrecoverable until/unless Polymarket extends their wallet contracts.

Can I unwrap pUSD back to USDC.e later?

Yes. The Collateral Offramp contract at 0x2957922Eb93258b93368531d39fAcCA3B4dC5854 converts pUSD back to USDC.e at 1:1. Simmer’s dashboard Withdraw flow routes through this when you withdraw a pUSD balance to your personal wallet.

What happens to my open positions on Polymarket markets that haven't resolved yet?

Positions (your outcome token holdings) are unchanged. V2 keeps the same ConditionalTokens contract, so token IDs, balances, and conditional payouts all carry over. What changes is the collateral the market settles into when redeemed — V2 markets pay out pUSD instead of USDC.e on redemption. You can still redeem winning positions post-cutover; you’ll just receive pUSD in your wallet, which you can keep or unwrap.

What happens to V1 limit orders I left resting on the book?

Polymarket wipes any V1 orders still resting at cutover. If you have open orders you want to preserve, cancel them before April 28 and re-place them as V2 orders after. Polymarket exposes the pre-migration order history at GET /data/pre-migration-orders on the V2 CLOB for reference.

Why pUSD instead of just using USDC?

Polymarket moved to pUSD to give V2 markets a single canonical collateral token that’s backed by multiple USDC variants (USDC.e today, native Circle USDC when Polymarket activates the PermissionedRamp). For users, the net result is the same:

1 of pUSD =

1 of USDC.e = $1 of USD. For traders who care about exchange rates, pUSD is always 1:1 with USDC.e on-chain.

Does the migration affect my agent's API keys or automation?

Your Simmer API keys stay valid. If your agent uses the simmer-sdk (Python), upgrade to version 0.12.2 or later — it auto-flips between V1 and V2 signing at cutover with no further action needed. (Versions 0.10.0–0.12.1 default to V2 unconditionally and produce order_version_mismatch errors against the still-active V1 CLOB pre-cutover; 0.12.2 fixes that.) If your agent constructs raw Polymarket orders (not via simmer-sdk), you’ll need to switch to the V2 order struct at cutover; see the integrator section below.

Troubleshooting

”Polymarket trading is paused for the V2 migration window”

Expected during the cutover window (~11:00–12:05 UTC on April 28). Kalshi and sim trading continue. Polymarket trading resumes ~12:05 UTC once the V2 exchange is live.

”Insufficient balance” when placing a V2 trade

You’re trying to trade V2 but your wallet still holds USDC.e, not pUSD. Fix: click Migrate to V2 on the dashboard banner. After the migration completes, your order should succeed.

”maker address not allowed”

Your EOA (the address Simmer signs trades from) has been blocked by Polymarket’s V2 CLOB. Polymarket requires a Deposit Wallet for all V2 order placement and has selectively enabled this requirement for older accounts. Wrap + approvals on your EOA alone are no longer sufficient. Fix: Go to your dashboard Wallets tab or look for the “Upgrade to deposit wallet” step in the migration banner. Click Upgrade — Simmer will deploy your personal Deposit Wallet smart contract. This is a one-time step. After the upgrade completes, re-set your V2 approvals (the banner will prompt you) and your next trade should go through.

”order_version_mismatch”

Your SDK is sending the wrong order shape for the active CLOB version. Fix: pip install -U simmer-sdk. Use 0.12.2 or later — it auto-flips between V1 and V2 signing at cutover. (Versions 0.10.0–0.12.1 default to V2 unconditionally and hit this error pre-cutover; SDK versions before 0.10.0 only sign V1 and hit this error post-cutover.)

“error parsing fee rate bps () to int64”

Usually the same root cause as order_version_mismatch — wrong SDK version for the active CLOB. Fix: upgrade to simmer-sdk >= 0.12.2. (Can also be a stale V2 CLOB cache after a fresh allowance change — in that case wait ~30s and retry, or call update_balance_allowance from the SDK.)

“bad signature”

The V2 order-signing domain differs from V1 (EIP-712 domain version "1" → "2"). Fix: ensure you’re on simmer-sdk >= 0.12.2, which sets the correct domain based on the cutover.

”Insufficient POL (gas) in your Polymarket wallet”

Your Polymarket wallet needs at least 0.1 POL to cover the approve + wrap gas for migration. This applies to both managed and external wallets — for managed wallets Simmer signs the transactions, but the gas comes from your wallet’s POL balance. Fix: the dashboard error message displays your wallet address; send a small amount of POL there from an exchange (POL is Polygon’s native gas token, available on most major exchanges), then click Migrate again.

Migration button stuck / transaction failing

Check your Polygon wallet has POL for gas.
Check your USDC.e balance is > 0 (migration does nothing if you have no USDC.e to wrap).
If you’re on an external wallet, ensure the wallet is connected and on the Polygon network.
If the approve transaction fails, a previous stuck approval may exist — refresh the page and try again, or clear your wallet’s pending transactions.

Still stuck

Ping us on Telegram or email simmer@agentmail.to with your wallet address and the error message. Include the tx hash if your transaction failed on-chain.

For integrators

This section applies to users building their own Polymarket order flow on top of Simmer (e.g., custom agents that construct orders directly rather than using simmer-sdk). If you’re using simmer-sdk, just upgrade to 0.12.2+ and skip this section.

V2 exchange contract addresses (Polygon)

Contract	V1	V2
CTF Exchange	`0x4bFb41d5B3570DeFd03C39a9A4D8dE6Bd8B8982E`	`0xE111180000d2663C0091e4f400237545B87B996B`
NegRisk CTF Exchange	`0xC5d563A36AE78145C45a50134d48A1215220f80a`	`0xe2222d279d744050d28e00520010520000310F59` (primary) + `0xe2222d002000Ba0053CEF3375333610F64600036` (secondary)
NegRisk Adapter	`0xd91E80cF2E7be2e162c6513ceD06f1dD0dA35296` (unchanged)	Same
Collateral token	USDC.e `0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174`	pUSD `0xc011a7e12a19f7b1f670d46f03b03f3342e82dfb`
Collateral Onramp (wrap USDC.e → pUSD)	N/A	`0x93070a847efef7f70739046a929d47a521f5b8ee`
Collateral Offramp (unwrap pUSD → USDC.e)	N/A	`0x2957922Eb93258b93368531d39fAcCA3B4dC5854`
V2 Fee Escrow (PolyNode fee collection; required pUSD approval)	N/A	`0x3A43D88ef8Aae4dF5a50B3abf67122CAAeEF7c9F`
CTFCollateralAdapter (bridges pUSD ↔ USDC.e for standard market settlement)	N/A	`0xAdA100Db00Ca00073811820692005400218FcE1f`
NegRiskCTFCollateralAdapter (bridges for neg-risk markets)	N/A	`0xadA2005600Dec949baf300f4C6120000bDB6eAab`
ConditionalTokens (CTF)	`0x4D97DCd97eC945f40cF65F87097ACe5EA0476045` (unchanged)	Same

V2 order struct changes

The EIP-712 signed struct drops three fields and adds three:

Field	V1	V2
`taker`	Required	Removed
`nonce`	Required	Removed
`feeRateBps`	Required	Removed (fees are match-time, read from the on-chain Trade event)
`expiration`	In signed struct	Moved — still in HTTP POST body at `"0"`, but dropped from the signed hash
`timestamp`	—	Added (milliseconds since epoch)
`metadata`	—	Added (bytes32, default `0x00...00`)
`builder`	—	Added (bytes32, builder attribution code — optional)

EIP-712 domain change

Domain version bumps from "1" → "2"
verifyingContract changes from V1 exchange to V2 exchange address

Python SDK quick switch

# Old (V1)
from py_clob_client.client import ClobClient

# New (V2)
from py_clob_client_v2.client import ClobClient
from py_clob_client_v2.clob_types import OrderArgs

client = ClobClient(
    host="https://clob.polymarket.com",
    chain_id=137,
    key=private_key,
    signature_type=0,  # EOA
    funder=wallet_address,
)

order_args = OrderArgs(
    token_id=token_id,
    price=price,
    size=size,
    side="BUY",
    expiration=0,
    builder_code="0x...",   # Your V2 builder code (mint at polymarket.com/settings?tab=builder)
    metadata="0x" + "00" * 32,  # Default zero bytes32
)
signed = client.create_order(order_args, partial_create_order_options)

Wrapping USDC.e → pUSD programmatically

# 1. Approve Onramp to spend your USDC.e
usdc_e.approve(ONRAMP_ADDRESS, max_uint256)

# 2. Call Onramp.wrap(underlyingToken, recipient, amount)
onramp.wrap(USDC_E_ADDRESS, wallet_address, amount_in_6_decimals)

amount is in raw 6-decimal units (1_000_000 = $1). The resulting pUSD lands in your wallet at 1:1.

After-approval CLOB cache refresh

V2 CLOB caches balance and allowance state per API key and rejects orders on a stale cache until refreshed. After any on-chain allowance change, call:

from py_clob_client_v2.clob_types import BalanceAllowanceParams, AssetType

for asset_type in [AssetType.COLLATERAL, AssetType.CONDITIONAL]:
    client.update_balance_allowance(
        BalanceAllowanceParams(asset_type=asset_type, token_id=None)
    )

Without this refresh, your first order after setting allowances rejects with "not enough balance/allowance" despite correct on-chain state.

​TL;DR

​What’s happening on April 28

​What you need to do

​Managed wallet (default for most users)

​External wallet (self-custody — MetaMask, Rabby, Coinbase Wallet, etc.)

​If your Polymarket wallet holds no USDC.e

​If you use Kalshi or sim trading only

​Timeline

​What if I don’t migrate?

​FAQ

​Troubleshooting

​”Polymarket trading is paused for the V2 migration window”

​”Insufficient balance” when placing a V2 trade

​”maker address not allowed”

​”order_version_mismatch”

​“error parsing fee rate bps () to int64”

​“bad signature”

​”Insufficient POL (gas) in your Polymarket wallet”

​Migration button stuck / transaction failing

​Still stuck

​For integrators

​V2 exchange contract addresses (Polygon)

​V2 order struct changes

​EIP-712 domain change

​Python SDK quick switch

​Wrapping USDC.e → pUSD programmatically

​After-approval CLOB cache refresh

​More reading

TL;DR

What’s happening on April 28

What you need to do

Managed wallet (default for most users)

External wallet (self-custody — MetaMask, Rabby, Coinbase Wallet, etc.)

If your Polymarket wallet holds no USDC.e

If you use Kalshi or sim trading only

Timeline

What if I don’t migrate?

FAQ

Troubleshooting

”Polymarket trading is paused for the V2 migration window”

”Insufficient balance” when placing a V2 trade

”maker address not allowed”

”order_version_mismatch”

“error parsing fee rate bps () to int64”

“bad signature”

”Insufficient POL (gas) in your Polymarket wallet”

Migration button stuck / transaction failing

Still stuck

For integrators

V2 exchange contract addresses (Polygon)

V2 order struct changes

EIP-712 domain change

Python SDK quick switch

Wrapping USDC.e → pUSD programmatically

After-approval CLOB cache refresh

More reading