I really don't know what the best way to fix this would be.

Rate limit /invite: Would make inviting a big team slow.
Rate limit after /uninvite: Don't know how best to implement this.
Put all server messages through antispam: Would be pointless in most cases

I don't have a macbook handy now but will check it out in a week or two on a friends.

Playing on Windows, and yeah same happens to me, cant connect to the server without chrusing it. @teddi If you are searching for server (menu when you start ddnet client normaly) on the bottom corner left. There should be an option to upgrade your client to the newest version. For me its not f.ckin...

It's for live servers. There just isn't a way to distinguish servers that have rcon auths setup vs default sv_rcon_password because we ran out of protocol messages. So I just display the username prompt on all servers that identify themselves as DDNet.

Yeaah, I'm not too good with choosing colors

C&P Is "copy and paste" basically while recoding the auth system I forgot that I wasn't using pointers anymore but indexes to an array, which answers your third question. A KeySlot is an index to a key in the key array.

OS, Client version, 64bit/32bit ? What happens when you try to join new maps ? Define updater won't work..

So: Start the client -> cl_http_map_download 0 -> Download map -> Always crash ?
If that's the case how does it work after a restart do you join the same server with cl_http_map_download 0 ?

Can you reliably reproduce this as in can you just make it happen whenever you want? I'm just confused as to how this can happen....