Bitcoin Forum

I just received my first Bitcoin today, and I noticed that a new bech31 address has been added to my wallet, while the previous bech31 address is no longer visible. So here's my question.

• What will happen to my Bitcoin if I decide to transfer some sats to the former address?
• Is this something I should be concerned about?

The Wallet name is MYCELIUM.

Your wallet generates a new address each time the "old" one receives bitcoin. It is not a bug, but a wallet feature that tries to protect you from unintentional address reuse. Address reuse is when you use the same address on a recurring basis. This is not against the rules of Bitcoin protocol to reuse your address, but it is kind of bad for your transactional privacy. So, after you receive a payment, you still have control over the address and you can reuse it freely. Don't be afraid of making transactions on the bitcoin network, but do it wisely. If you are unsure if your payment will reach its destination, try to send a negligible amount first and see if it succeeds.

There is no bech31 address. What you are talking about is bech32. They are addresses that start with bc1.

You will receive the fund and there's nothing to worry about. You have numerous addresses all generated from a single seed phrase and you can use any of them.
Take note that all bitcoin transactions are publicly recorded on the blockchain and anyone in the world can see them. That's why your wallet generates a new address for you, so that you can protect your privacy if you are going to receive another bitcoin transaction.

The concern is privacy-related. No, you don't harm anything other than your privacy when reusing a Bitcoin address.

A similar, common question is the change addresses. If you haven't noticed already, your wallet software is likely to categorize addresses in "receiving" and "change". The former is when you hand over an address to someone, and expect to receive funds. The latter is, as the name suggests, your change; the destination after you've spent a transaction output (https://en.bitcoin.it/wiki/UTXO), just like in real life when the cashier gives you change.

Your Bitcoin will be joined together and anyone could identify different sources you used to send coins, that can reduce your privacy.
Using same address would be fine if you are receiving Bitcoin from same source, that could be your public donation address that is used to receive payments.
In all other cases you should generate fresh new address and try to do address management with labels for addresses and transactions.

This is standard for bitcoin wallets these days.

What you are using is called a BIP32 wallet which is a standard for HD wallets which stands for hierarchical deterministic (not high definition). HD wallets are a privacy feature so that we are not all giving away a bunch of our personal financial info away to the entire world every time we send/receive bitcoin.

It's best to only use an address once but if you receive multiple payments to an old address from your wallet, you will still receive the bitcoin.