I search thru the forum and couldn't find a definite answer for the activation related issues before and after 2018

Here is my situation:

I have 2015, 16, 17 and 18 installed on my home computer and activated as a standalone license.

I have 2015, 16 and 17 installed on my laptop and activated and use once in a while whenever I meet with my clients (both works as per the pre 2018 licensing terms and conditions in North America)

Here is my question:

If I use the new online license activation/de-activation tool, does that affect the 2015, 16 and 17 versions or it's just activate only 2018 and 19 versions?

If I want to use to install 2018 and 19 on my laptop and use whenever I am away from my home computer, does the online tool affect the activation of previous versions?

Can someone with multiple version, please share your experience

Thanks!