It installs a separate version leaving LR5 as is. It will also COPY & CONVERT your LR 5 catalog to a LR 6 catalog.
Thanks. Any idea of the file size for the download? Plus would have the same with PS 5
Well the download is around 1gb and the instal I slightly more.
If you will buy subscription , yes you will get an extra copy of Lightroom that is Lightroom CC.
Lightroom CC will not override your Lightroom 5 Catalog and settings.
However when you will open your catalog of Lightroom 5 to Lightroom CC it will ask you to upgrade the catalog and then it will create a copy of the catalog with upgraded settings.
Now if you want to use the same catalog in Lightroom 5 you need to open the previous catalog of Lightroom 5.
One thing that I would like to make you in notice that you can upgrade the catalog however you cannot downgrade the catalog from Lightroom CC catalog to Lightroom 5 catalog.