/expert has been replaced with /worldmode.
Whips should work again
This is a release that is suitable for private servers with trusted players: several anticheat checks have been disabled due to changes in the Terraria protocol. These checks include projectile spam checks and net modules (liquid exploits in particular). We highly suggest making a backup of your world (and potentially any existing server data you have). This is also an interesting release because it includes changes that have been in development for quite some time. If you're a plugin developer, now is the time to start updating. More breaking changes may happen, but there will always be an updated API version to track.
Enjoy :)