Depending on when you started using Blockstream Green, the timelock feature might already be activated for your wallet. That's because on January 25th, 2021, Blockstream Green switched its timelock script from nLockTime to CheckSequenceVerify (CSV). While the new CSV timelock feature is activated by default so long as your application is up to date, the nLockTime timelock feature needs to be activated manually. To learn more about the mechanics of the switch from nLockTime to CSV, read this article. Whether there are funds in your wallet that still use nLockTime depends on when you first used Blockstream Green: If you created your wallet after January 25th, 2021, your wallet only uses CSV timelocks. That means the feature is activated by default, and no further action from you is required. If you used Blockstream Green before January 25th, 2021, you likely have nLockTime-secured funds in your wallet. To make use of the timelock feature for these funds, you must activate it in your settings—if you don't, you could lose access to your funds if the Blockstream servers become permanently unavailable or you can no longer access your two-factor authentication (2FA) methods. Follow the steps below to activate the timelock feature. You can only activate and modify the timelock feature in your desktop application. Note: Timelocks can only be activated for Blockstream Green Bitcoin standard wallets (2-of-2). Liquid wallets only use CSV (which means timelocks are activated by default), and Bitcoin 2-of-3 wallets do not require timelocks as you can always combine your third backup key with the key on your device to recover your funds. 1. In your Blockstream Green desktop application, log in to your Bitcoin wallet. Then click the Settings icon (displayed in the form of a gearwheel) in the top right corner of your screen and select the Recovery tab. 2. The timelock feature is only available if you enable email notifications. To do so, you first need to set a recovery email address. Under "Set an email for recovery," click Enable. Note: Make sure to set an email address only you have access to. Every time you make a transaction, you will receive an email containing a transaction that has been pre-signed by the key held on the Blockstream servers, but locked until the nLockTime period has passed. Once nLockTime expires, the transaction is spendable using your recovery phrase combined with the garecovery tool. It is further recommended to use a pseudonymous email address. 3. Enter your email address and verify it by pasting the confirmation code that is sent to the email address you provided. Then click Next to activate your recovery email address. 4. Open the General tab. Under Notifications, activate the toggle next to "Receive email notifications for sent and received transactions." 5. Timelocks are now activated for this wallet. Note: The timelock feature only applies to the wallet within which it is activated. If you want to set up timelocks for other wallets, open the respective wallets and repeat the process. By default, the nLockTime period (the amount of time required to pass until pre-signed transactions sent to your email address become spendable) is set to 12,960 Bitcoin blocks, or around 90 days. You can view or change the nLockTime period in your settings.