a confusion regarding package updates

[Tapas Mishra]

I have some confusion regarding a server of mine.
When ever I ssh into it I see following message

 Graph this data and manage this system at https://landscape.canonical.com/

125 packages can be updated.
77 updates are security updates.

Before I do any command as below
 apt-get update && apt-get -y upgrade > /dev/null

I want to make sure it does not upgrades from 10.04 to 10.10 I do not
want the OS version to change.
So can any one tell as if the above way of doing(installing updates
and security updates) is correct or not.
I remember in past I had upgraded my laptop and installed a test
release so every thing had broken on my laptop.
Hence asking it.

-- 
Thanks
Tapas