Quote from: Stedsm on November 04, 2017, 08:45:49 AM
What about the old P2PKH addresses? I mean will they be included in the Bech32 (native segwit) format?
No, BIP173 (though it is still draft) specifies Bech32 only to P2WPKH and P2WSH. It may be extended to include older formats but I think it won't because it will only confuse people.
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Is there any difference in using the old addresses? Shall I stop using the P2PKH and/or P2PSH addresses?
Old P2PKH and P2SH addresses are going to work. It is the only way to ensure that old coins are spendablle so I guess it will be supported as long as Bitcoin exists.
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The addresses that blockchain.info provides nowadays, do they all come under the SegWit Protocol?
Segwit protocol is a broad and complicated thing. All the blocks mined are already under segwit protocol. In theory, there can be a non-segwit block mined with only non-segwit transactions but I think all the miners upgraded software so it does not happen.
BIP141 defines 4 segwit payment methods:
P2WPKH
P2WPKH nested in P2SH (P2SH-P2WPKH)
P2WSH
P2WSH nested in P2SH (P2SH-P2WSH)
P2WPKH and P2WSH are native segwit. Both spending and receiving requires segwit-aware wallets. The addresses are bech32 encoded. For P2SH-P2WPKH and P2SH-P2WSH only spending requires segwit-aware wallets (but relaying and block validation can happen also on non-segwit aware node). Anybody (with BIP9 P2SH-aware wallet) can send to these addresses because they look (and the output behaves) the same as non-segwit P2SH. They are provided to ease the transition to segwit. The nesting in P2SH induces an overhead so native segwit transactions are smaller. Only at input it is revealed if the address is P2SH only or P2SH with witness. Both look the same (starting with 3)
Currently, very few of the native segwit transactions are happening. But it is slowly growing. If you don't care about receiving (say, a wallet for sending with occasional top-up, many exchanges have such wallets), you can use it right away and save on fees. P2SH-P2WPKH is more universal but the transactions have higher size (and fees), though still lower than non-segwit P2PKH or P2SH.