Most Bitcoin wallets these days support BIP32, Hierarchical Deterministic Wallets. This enables a user to keep track of a single piece of data from which a nearly infinite number of public/private keypairs can be generated deterministically. As Bitcoin wallets have increased in complexity over the years, there are now a variety of different versions of extended public keys. You can convert an extended public key from any version to a different version by changing the "version bytes" but this is hard to do if you aren't an experienced developer. This tool makes it simple for anyone to convert between different versions.
Bitcoin wallet developers may find this tool helpful during testing, such as for switching between mainnet and testnet versions.
Bitcoin users may find this tool helpful if they are trying to import watch-only wallets into software that expects a specific version of extended public key with regard to the paths used for key derivation.
This tool uses version bytes as described in SLIP-0132
The Bitcoin Extended Public Key Converter is released under the terms of the MIT license. See COPYING for more information or see http://opensource.org/licenses/MIT.