Bitcoin Core 22.0: Supports I2P, Hardware Wallets and Full Taproot

Bitcoin developers have released Bitcoin Core 22.0 client version, which is called the largest update since the activation of SegWit in 2017.

Possibly the words about “the largest renovation in four years” exaggerate the meaning
this release, but it does include some pretty important and expected features. To show its importance, the developers even went for a change in the client’s numbering. From version 22, the leading zero has been removed, usually indicating that the program is in a test version. So instead of 0.22, users saw 22.0.

Usually, it is customary to assign integer numbers to products that have entered commercial operation, and the numbering starts from 1.0. But the developers of Bitcoin Core chose the “unconventional” path, deciding to show that Bitcoin is no longer a test product, although there are no revolutionary innovations in this version.

So what will Bitcoin Core 22.0 do for you?

The “highlight of the version” in the media announced the inclusion in the code of full support for the Taproot technology, which increases the anonymity of transactions and allows the execution of more complex smart contracts than those laid down in the basic scripting language of Bitcoin. However, the developers themselves have not announced significant innovations in this area.

The main Taproot code was added to Bitcoin Core a year ago, and in version 0.21.1, the Speedy Trial activation mechanism also appeared. In 22.0, protocol rules have been added and updated to support transactions using Taproot. They will start working after activating the update, which is also checked in the new version.

I2P – more anonymity

Bitcoin Core 22.0 adds full support for another anonymous connection protocol – I2P (Invisible Internet Project) – for increased anonymization of nodes in the peer-to-peer network. This network allows you to hide not only the IP addresses of the nodes, but also the transmitted messages themselves using multi-level encryption. The possibility of anonymization through Tor is preserved, but support for the outdated version of the Tor protocol v2 is disabled. Now only nodes with support for Tor v3 and beyond will be able to connect through this network.

Hardware wallets via GUI

Support for external devices for signing transactions (mainly hardware wallets) appeared in version 0.18.0, but previously you had to work in the command line to use them. Now with the help of an optional installable HWI module, a hardware wallet or other device for signing (external signer) can be connected and managed through a graphical interface.

Updated the mechanism for calculating commissions

To avoid paying higher fees to miners, the new wallet has expanded the use of the Child-Pays-For-Parent (CPFP) method. This function first sends the transaction with the minimum commission, and if necessary to speed up it, a payment with a higher one is sent to replace it.

Bitcoin Core 22.0 now has the ability to check the filling of the mempool before sending a transaction, and can, at the most appropriate moment, send both transactions simultaneously in order to exclude them from falling into different blocks. Using the testmempoolaccept command, you can send bursts of up to 25 transactions in this manner, totaling up to 101 KB in size.

Other changes

Among the changes that are less important for the average user are:

• New method for building a wallet for Linux. For Linux users, Bitcoin Core now uses the new GUIX package manager.

• The number of possible signatures for multi-signature transactions has been expanded (also used in SegWit and Lightning Network). Now, instead of 16 keys, you can sign transactions with a maximum of 20 keys.

• A new Bech32m address encoding mechanism has appeared instead of the classic Bech32.

• The blacklist of hosts and subnets is now stored in the banlist.json file instead of banlist.dat.

• You can now use NAT-PMP for port mapping.