Due to a serious bug in the Minecraft 1.8.2 server, Mojang Team was released an update to Minecraft 1.8.3. It’s now available through the Minecraft launcher.
Because this is important, let me repeat that last sentence:
Please make sure that you are in the correct server mode (online mode/offline mode) when you start the 1.8.3 server for the first time, because profiles are not compatible between these two server modes.
Cross-platform server jar: https://s3.amazonaws.com/Minecraft.Download/versions/1.8.3/minecraft_server.1.8.3.jar
Cross-platform server windows exe: https://s3.amazonaws.com/Minecraft.Download/versions/1.8.3/minecraft_server.1.8.3.exe
Credits: Mojang Team