I double checked servertest.ini and also tried the changeoptions-command again. I am able to see SleepAllowed in both places (.ini-file or server console) but I cannot find SleepNeeded. When typing changeoptions SleepNeeded true I get response Option SleepNeeded doesn't exist. If I do the same with SleepAllowed it replies that the option is now the changed value.
I did intial changes to servertest.ini using "PZServerSettings.bat" that is located in the game folder. After that I also read the .ini file using Notepad++ and might have done some modifications. Just saying in case that could cause anything...
I tried adding SleepNeeded in the servertest.ini manually but it gets removed. Thus, I started wondering if it's implemented in the latest IWBUMS.
EDIT: When starting the server, the console is saying that versionNumber=34.15