Hello,
“Version” here refers to the version encoded in the public address, as described here https://en.bitcoin.it/wiki/List_of_address_prefixes and further explained here https://bitcoin.stackexchange.com/questions/546/what-is-the-meaning-of-the-bitcoin-address-version
When this field is available, the bs58check script is used to validate addresses. The user will see a warning if they enter an invalid address.
If the version is missing, addresses are not validated on the frontend. Invalid addresses will still be rejected by your wallet in the backend.
with regards