will 1.2 be used in the already running games. If it is not, I will leave the games and play only the latest version.
No.
Please read the news. https://www.airwaysim.com/Information/News/#110
The changes in v.1.11 vs. v.1.2 are not so dramatic so I'd rather advise to play the current v.1.11 worlds for now.
lol oh sorry didn't read it all.