I did a quick check of the XKT Patch, and there are a bunch of bad mistakes or incorrect things, so here are some explanations (some are actually from there : topic11-31376.php )
1) As stated in the License (here : C:\Program Files\Tennis Elbow 4\Game\Doc\En_License.Txt ) :
You shall not remove any Tennis Elbow nor Mana Games logos from the menus, nor remove any existing credits.
XKT removed the official credits and packed them quickly at the end of their credits.
Instead, you should do 2 buttons : official credits, mod credits.
2) XKT copied all the SDK files in their mod, even the unmodified ones ; it means, game updates (that can fix and/or improve the game) won't work with the patch.
Solution = XKT should delete all the unmodified files (which will in bonus make the installer file smaller)
3) There are Mac users around there, plus Windows users who don't like .exe installer, so it'd be good to have a .Zip version of the installer
4) There's a lang_English.txt, which is already outdated, so instead XKT should use lang_English_Mod.txt containing only the added or modified entries (so the mod will have a much higher chance to work with future game updates)
5) There's a lang_Simplified Chinese.txt , but the actual file should be lang_简体中文_Mod.txt (with, again, only the added or modified entries)
6) You cannot put a link to any other website than managames.com ; I can add a redirection from managames.com to your website or discord channel, but it has to follow 1 important rule : do not advertise concurrent tennis games, delete such messages, and eventually ban people who do that after a few times.
7) You didn't follow the rules to add new service animations ; load all the new service anims in the Character Sheet customization screen, then look in the player.log for "===> Service"
8) In a general way, look for "Warning:" and "Error:" and you'll find many problems reported by the game : if possible, it's better to fix them all before releasing the Mod