I see outdated servers on and off, it get's pretty annoying, there is a reason why you shouldn't host servers like them.
First of all, it is outdated. I understand you like the old maps, but you should just get over it, making maps are considered laziness. Making maps out of bricks is the best you can do, while maps are out of date (Pretty old), they might come back, or never; I have warned people that say "Hey you should download v20 (or whatever version they said) so you can come to my server.", not to host because there is a possibility of getting banned from the master server, not that I don't like them or something like that; of course, no one will really care about it because they don't either believe it or just don't care at all if they host the outdated server.
Second, you might get banned from the server. As said above, you can get banned from the master server of hosting, that might not matter to you, but it should because you shouldn't really host servers under the current version. There is a reason why things are not compatible after a big update.
This topic may be WAY too late, but I haven't seen any topics about it like this. I am just giving my opinion.
