97d+99i+ main.exe doesn't load (********* server side+client side)

Hello. I want to say that it is my first them when i`m trying to make a mu server (only local, not open to public or something like that) and some things are completly new to me.
What i have and what is my problem. Well, I have a realease from ignetwork that is 97d+99i+ with server side and client side. The client side is divided in 2: original and customized.
Good.. I mananged to open all servers, setting the ip-s, making an account. The problem has 2 parts: 1. If i open the client with main.exe from original client, i manage to enter untill account, writing it and when i press enter it gives me an error: New version of game is required. Please download a new version of the game. // 2. If i open the client with main.exe from customized client, it doesn't even load the game. It reacts like nothing happened.
What I have tried to do:
- i tried to do something with hexedit+HxD+ultraedit. to be honest i don't know what i have to do.. I think i have to modify the Key and Version from main.exe
- i tried to edit Key and Version from main.exe with Main Editor.exe, but Main Editor it turns off (error) after i click Open and select main.exe
- i tried to build a launcher (Zyth3, Global and PerX). No luck..
- i tried to download some clients from other server and use Main Editor.exe on them. 0 luck.
- and some other stuff that i don't know how to explain. and for sure are useless.

What I would like to ask for: if someone can guide me to what I have to do.. Not necesary to edit my main.exe or what it needed to do.. But i don't know what i have to in order to enter in server from client, and if i would know what to do, for sure i would not know how to do it.
As a last effort from me to understand those servers/clients/ip/port/ editing things I beg someone to help me somehow.

thanks a lot for reading and sorry for my english! have a nice day/night!

edit: from /muserver/data/lang/kor/commonloc: client version 0.97.04 and serial DarksTeam97d99i+

has opened the port?

I have router and I opened ports 55901, 55913, 44405, 55557.

Edit: I don't know how to check what port is in main.exe. Can anyone tell me? Also, what is the importance of "Key" from main.exe?

your problem = you need to enter the client with launcher.rexe or with main.exe (the custom one)
u said it says wrong serial version bla bla, well u have to fix that.. then u can maybe enter in game.
how? in ur main.exe search for the serial or version if u can find, both are on the similar offsets if u find, then change them and change in client side and then retst.. cus if it worked with other main.exe then means Ports opened, u can check at Open Port Check Tool
u also only need to open 44405 and 55901 thats all.

altenrative solution is usually connecting with skyteam launcher builder or other launcher where u config with ip/port settings etc and connect directly with those settings to the server.

Thank you for response. Meanwhile I managed to resolve the problem. I have found another client, took the main.exe and I edited the ip.