That (support) was a dead end.
"Please note that Since the 1st of September 2017 v14 is no longer supported, The only way to fix this and be able to manipulate extensions is to upgrade to v15 and also regain support."
I don't have any installations that actually use or rely on webmeeting. It's just a piece of fluff that will never get used in real life blue collar nuts and bolts businesses. I'd be willing to bet that a lot of businesses don't use it. It's a shame to have it wreck a decent product in this way.
Founded in 2005, when VoIP was an emerging technology, 3CX has gone on to establish itself as a global leader in business communications.