Will any network participant be able to send to a native segwit address? Does a wallet have to upgrade to send to a native segwit address provided by the recipient or can anyone send to them, as was the case with the P2SH-wrapped segwit addresses?
In the compatibility section of BIP-0173, it states:


  Only new software will be able to use these addresses, and only for receivers with segwit-enabled new software. In all other cases, P2SH or P2PKH addresses can be used.