Changing what your Minecraft server is running (the JAR file)

1. Stop your server.

2. Login to FTP or use the file manager.

3. Get bukkit or Spigot https://getbukkit.org/

4. Delete your old minecraft_server.jar file.

5. Upload the new jar file.

6. Rename the jar file to minecraft_server.jar (very important jar name is the same as before).

7. Start your server and you will see the plugins folder and other folders build.