just a bit of an explanation why removing of version numbers for scripts/stylesheets is a bad idea:

consider the following scenario:

with version numbers removed you get the following in your page
http(s)://www.domain.com/wp-content/plugin/some-plugin-or-theme/script.js
instead of
http(s)://www.domain.com/wp-content/plugin/some-plugin-or-theme/script.js?ver=2.0

(assuming for this exercise it’s version 2.0 intitially for the plugin/theme for example)

so, when someone comes to your site, their browser will download
…./plugin/some-plugin-or-theme/script.js
so far so good.

now we assume that plugin/theme gets updated to v2.1 (2.2,3.0, whatever) with changes to that javascript file (like added ajax request for example or whatever else you can think of)

a day later, after you have updated the plugin, that same person comes to your site again and what’s going to happen – not always, but there’s a distinct possibility – is this:

browser reads page and still finds
…./plugin/some-plugin-or-theme/script.js
browser says “oh, I already have that file in my cache, no need to download it again” so uses that cached version. of course, that version does not have those added ajax request etc and your site will fall over / not work / have issues

if it had a version number, the browser would have known it’s different and would have downloaded that new file instead of using the old expired one…..
same would go for css and any other linked files too (how about a css saying originally display:block and then display:none somewhere , etc etc)

the above is just to get you an idea and not comprehensive or complete (there are ways to overcome this in other ways, but that’s a different conversation and – in any event – overkill, unnecessary and personally speaking silly given that the whole version numbering is there for exactly that purpose)