Theme Update – A Basic Question

Hello, my question seems to be so basic that, apparently, no one needed to ask . . . looks like.

Q: If I update the themes I AM NOT USING, meaning they are not activated, do I have to worry about the warning for “loosing the changes?” : (

I want to get rid of the “Update” notice, but am afraid something can happen to my theme that I am using if I update them because of the warning. I am not using 2011 or 2012, and those are the ones that are up for updates.

This may sound so stupid, but I want to make sure. Or, how can I get rd of the “Update 2” notice up on the Dashboard? or can I?

Thank you for reassuring me : )