I want to make my own plugins for a 1.8 server that has support up to 1.17. Do I need to redo the plugin for every version of minecraft? Im using Eclipse and the Spigot server as an external jar.
No, you just need to use bukkit methods which are found on both 1.8 and 1.17. You can mostly accomplish this by writing the plugin for 1.8 and avoiding using legacy or modern BlockData classes. If you need to use block data, you can compile against two bukkit API versions and determine which one to use based on what versions your server is.
I would also suggest to move to maven or gradle to make everything related to dependencies easier. It’s better to learn now.
Thanks a lot. I will definitely do that.