I get this issue when running step 3
root@rocketchat-ubuntu-s-1vcpu-3gb-nyc1-01:~# sudo rocketchatctl update
Updates could be risky, you can use the backup option # rocketchatctl backup, to create a backup of the rocketchat database first. Please check that you have en ough space in your system to store the backup.
/usr/local/bin/rocketchatctl: line 897: [: 3.0.5: unary operator expected
Could not determine if updates available for RocketChat server.