Wordpress - Update Wordpress with SFTP instead of FTP

Configuration instructions in Codex on Enabling SSH Upgrade Access recommend either:

1. Using SSH SFTP Updater Support plugin from official repository.
2. Using built–in SSH2 support, which requires the PECL SSH2 extension installed on the server.

It used to refer to this tutorial: Using SSH to Install/Upgrade in before, which might be of use.