How will I know I can upgrade my server?

Tue Jul 31 00:07:33 UTC 2018

https://wiki.ubuntu.com/BionicBeaver/ReleaseNotes mentions that when the 
upgrade from 16.04 to 18.04.1 is available, I should run `sudo 
do-release-upgrade` to upgrade my server. But how will I know when the 
upgrade is available? Is there a tool or mailing-list for that? Because 
it makes it seem that I should run the command by hand until the update 
appears.