*** Error, this build is outdated *** *** Please download a new build as per instructions from https://www.spigotmc.org/go/outdated-spigot *** *** Server will start in 20 seconds *** How should I solve this?
Either build a newer version of spigot with buildtools, or if you prefer to use an older version, and can't wait 20 seconds, adding "-DIReallyKnowWhatIAmDoingISwear" in your start.bat right after java will ignore the fact that it's outdated.