Moving a legacy token balance can take one transaction or several days, depending on the issuer’s migration method and deadline. First check whether the old balance needs a separate conversion; a wallet showing tokens does not mean they are the current version.
- A token balance belongs to a specific contract address, even when its name and ticker match a newer token.
- Use the migration steps and contract address published by the token issuer.
- Check the network and fee before signing; a bridge transfer does not convert an old token automatically.
What does a migration change?
A token migration moves or converts your balance from one token contract to another. A contract is the on-chain program that records token balances and transfers. The old balance can remain visible after migration, even if the issuer has stopped supporting that token.
EIP-20, the Ethereum token standard, defines a balance for each token contract and wallet address. It does not provide a universal button that upgrades old tokens. The issuer may ask holders to send tokens to a migration contract, claim replacements, or follow another process.
If you want to move the replacement token between Ethereum and Mantle, check that the exact token is supported before bridging. The official Mantle Bridge is relevant once you have the live token balance, because a bridge moves supported assets between networks; it does not decide which contract replaces an old one.
How do I check the right migration route?
Start with the issuer’s official announcement and compare the old and new contract addresses. A token name or ticker alone is not enough: different contracts can use the same label. Confirm the network, conversion ratio, deadline, and whether the issuer says the old token can still be moved.
Then check where your balance sits. A balance on Ethereum, Mantle, or an exchange may need a different route. If it is on an exchange, follow that exchange’s notice; if it is in your own wallet, the issuer’s instructions should say which network and wallet actions apply.
Only connect your wallet through a route linked by the issuer’s verified channels. Read each wallet prompt: an approval gives a contract permission to spend tokens, while a transfer or claim performs a separate action. Do not approve an unlimited amount unless the instructions clearly require it, and never share your recovery phrase.
What will it cost, and how long will it take?
There is no standard migration fee or completion time. A wallet transaction usually requires a network fee, called gas, paid in that network’s native coin. An issuer may also set a claim window, conversion rate, or service charge. Ethereum.org’s contract-upgrade guidance notes that moving balances between contracts can require manual work and gas.
For example, say you hold 240 old tokens and the issuer confirms a 1:1 conversion. If its migration contract accepts your tokens, you might approve the contract, then submit a migration transaction. After it confirms, check the new contract’s balance; do not assume the old tokens vanished or that the new ones will appear under the same wallet display.
The key delay is often the issuer’s rules, not the transaction itself. A transaction can confirm quickly, but a claim may stay unavailable until a published date or review period ends. Keep the transaction record and check the new balance on the correct network.
What if the old balance is already on Mantle?
Do not send it through Mantle Bridge until you know whether that exact token contract is supported and whether bridging is part of the issuer’s migration steps. A bridged token is a network-specific representation of an asset; matching names do not prove that it is the replacement token.
If the issuer requires migration on Ethereum, you may need to move the supported old token there first, then follow the issuer’s conversion process. Check both the source and destination contract addresses before signing, since each network can show a separate balance.
Keep a small record of the old and new addresses, the deadline, and each transaction hash. My practical tip: confirm the new-token balance on its stated network before you move or trade it.