suddenly I found that the mod planes became invisible, (this is the same as the server default) before the update, all planes were visible
Mod planes are never visible on a stock server.
It just doesn't work that way.
Whatever you think you saw there... nope, doesn't work.
You need to have mod planes installed on all participating clients
and the server in order to get them to work.
If you don't have them on the server, then each client will just see their own planes, but none of them will be replicated over the net, simply because they can't.
where can I download the BAT server? The one you are talking about.
There is no such thing like a BAT server download.
It's been stressed a few million times that BAT is offline only.
You have started with claiming to have BAT 3.7 working on a dedicated server, but now it turns out that you never had that apparently.
So... The
theoretical path would be:
Install a Stock 4.12.2m Server.
Install BAT on top, all the way like you would for a Client.
Install The IL-2 Selector Server files on top.
Try.
Really, try it. You're doing something that's not officially supported, so you have to try yourself. YMMV.
Mike