For how long can I wait to do a release-upgrade on Server 18.04.6 LTS?

[Bo Berglund]

I have an Ubuntu 18.04.6 LTS server running inside a VMWare Esx virtualization
server. It is located across the ocean from where I live and I am only able to
use SSH (through PuTTY) to access it for maintenance.
This is done via a OpenVPN connection into the LAN it lives on.

The Ubuntu was release-upgraded a number of years back from 16.04, which I
believe was first installed on Feb 18 2018 (before 18.04 was released).
(At least that is the date of the files in /var/log/installer/)

So now when I log on I am getting the nag message (only when it is fully
upgraded on 18.04):

New release '20.04.4 LTS' available.
Run 'do-release-upgrade' to upgrade to it.

I would have done this upgrade 2 years ago if I had not been prohibited to
travel to the main office in Texas due to Covid-19....

Now there is soon an official new release 22.04, and I have yet not been able to
schedule a visit...

Questions:

1) Will it be possible to upgrade from 18.04.6 to 20.04 after 22.04 has been
released?

2) If so, is there some mechanism in sudo do-release-upgrade which makes sure
that it won't grab the 22.04 release rather than the 20.04?
I think I would not like to risk skipping one release in the upgrade...

IOW:
Can I wait with the do-release-upgrade without bad issues hunting me when I am
in fact able to handle the upgrade on location after summer?


-- 
Bo Berglund
Developer in Sweden