This version is fully compatible with all previous 1.8 versions, but it is still highly recommend to update to 1.8.6 as soon as possible.
Notable fixes in 1.8.6:
- Exploit with signs and command blocks
Please make sure that you are in the correct server mode (online mode/offline mode) when you start the 1.8.6 server for the first time, because profiles are not compatible between these two server modes.
Cross-platform server windows exe:https://s3.amazonaws.com/Minecraft.Download/versions/1.8.6/minecraft_server.1.8.6.exe
Credits: Mojang Team