What will KB 3093594 do to Windows Live Mail 2012?

Split from this thread.

I am running OS 8.1 with Outlook with Windows Live Mail 2012.

If I download this new version of the Outlet mail that I am asked to do to continue e mail service what can I expect with this new program?

What will I loose?

What will I gain?

What will it do with my live mail 2012 version?

Will I be getting a bunch of advertising along with my mail?

Finally, I am thinking of going to OS 10 later, will I have to make more changes if and when I do change operating systems?

My reason for changing operating systems later is I only want one set of problems at a time.

Thanks