Hello everyone,

With my team we are working on a walleting application which ideally will generate a bech32 address when receiving from a bech32 compatible wallet, and a P2WPKH-nested-in-P2SH address when receiving for a legacy wallet. However, it is of course impossible for the payee to know in advance the technological capabilities of the payer, so a solution could be to encode in a Bitcoin URI both bech32 and P2SH addresses in a way that legacy wallets only see the P2SH address, while new wallets can also see the bech32 address and use it to perform the transaction.

In particular, to keep compatibility with BIP21, the <address> field of the URI can be used for the P2WPKH-nested-in-P2SH address and a new field (e.g. <segwitaddress> or <bech32address>), which will be ignored by legacy wallets, can be used to encode the bech32 address. The assumption here is that the wallets using such scheme will monitor incoming transaction both on the P2SH address and on the bech32 address.