Hello, please note: windows XP : use original RBST_BETA154.exe it is in RBST_winXP_RB-server-security.zip windows 7 and up (upto but not including windows 10 and later ) use download rbst_pre_win10.zip windows 10 and later downliad rbst_win10.zip Functionality remains the same : it blocks player with invalid checksum. How to checksum : To find out checksum for your new flightmodel patch : install proper version (see above) of rbst / winpcap run server, and rbst. enter with your flightmodel loaded the server and fly. you will be blocked. close the rbst the log file will be produced, the checksum that belongs to your flight model is logged at the bottom of the log file. use this in RBST.INI and you will be allowed to fly this flight model. enjoy. RBST_BETA154.exe allows you to run a redbaron server with security OFF, by taking care of checking the checksum of every player joining the game in place of the redbaron server. you need to have (on the server computer ) winpcap installed, to make it work. download here, or at https://www.winpcap.org/ in this way, you can fly any flightmodel modification and still have basic security. it checks only flight model security / integrity : ( just like redbaron security ) - acspecs files - ??damage files - fmparam* files - wingj* files it does NOT check : landmarks (the map ) locations like aerodromes, bridges, etc TED files for that, you need rssplyr.exe and rss server, and allow rss server to contact your rssplyr to check all these settings. check elsewhere on this site. S! Rens