I have a huge website which gets a lot of traffic so it can't be down for very long. The site is still running 1.6.7 (I know, shame on me!). I'd like to move it to a new directory on my server and take my time upgrading the back end before going live with it. Do I need to install 1.6.7 in this new directory and then upgrade from there? I've been putting this off for ages because frankly, I'm terrified of it.
Also, assuming it takes me a month to get the new site the way I want it (I'm redesigning as well), when I switch to the new site, all of the information that's been added to the live site in the meantime will be missing. Is there any way to prevent this other than doing double entries using the two different dashboards?