Blockstream reopened multisig account creation in its app on October 13. For Bitcoin holders choosing between the two account types, the important difference is how they recover funds without two-factor authentication (2FA).
In a 2-of-2 account, normal spending uses your device key and Blockstream's server key. Each deposit has its own timelock. Once that expires, those coins can be spent with your key alone. The default is roughly a year, so losing access to 2FA can leave a wait before that recovery route opens. The app prompts users to redeposit coins to renew their 2FA protection.
A 2-of-3 account adds a second recovery phrase for you to keep offline. Combined with your device key, it lets you recover without waiting for a timelock. Everyday sends still use the device-and-server arrangement. This option is Bitcoin-only, not available for Liquid.
The choice is an extra backup to safeguard versus a possible recovery wait. Blockstream's recovery tool is separate software; building that recovery functionality into the app is still on its roadmap. Existing legacy multisig accounts don't need to migrate.
Sources:
https://blog.blockstream.com/multisig-is-back-in-the-blockstream-app/
https://help.blockstream.com/blockstream-app/manage-2fa-accounts/2fa-multisig-protection-explained
In a 2-of-2 account, normal spending uses your device key and Blockstream's server key. Each deposit has its own timelock. Once that expires, those coins can be spent with your key alone. The default is roughly a year, so losing access to 2FA can leave a wait before that recovery route opens. The app prompts users to redeposit coins to renew their 2FA protection.
A 2-of-3 account adds a second recovery phrase for you to keep offline. Combined with your device key, it lets you recover without waiting for a timelock. Everyday sends still use the device-and-server arrangement. This option is Bitcoin-only, not available for Liquid.
The choice is an extra backup to safeguard versus a possible recovery wait. Blockstream's recovery tool is separate software; building that recovery functionality into the app is still on its roadmap. Existing legacy multisig accounts don't need to migrate.
Sources:
https://blog.blockstream.com/multisig-is-back-in-the-blockstream-app/
https://help.blockstream.com/blockstream-app/manage-2fa-accounts/2fa-multisig-protection-explained