" Notes for Developers The 1.13 API is largely not backwards compatible with older versions. This means that if your plugin targets native 1.13 support it will NOT be able to run on < 1.13. Whilst forwards compatibility has always been a design goal of Bukkit, backwards compatibility has not been. If you wish to maintain support for older versions (e.g. 1.8) then you will need to concurrently develop two versions of your plugin. It is our hope however that going forwards only recent Bukkit versions will be supported by developers as this is the best way for the community as a whole to keep evolving. Once you have made the necessary changes to your plugin to enable successful compilation against the 1.13 API, you must add the following to your plugin.yml: Code (Text): api-version: 1.13 This will signal to the server that your plugin has been coded with 1.13 in mind, and that it should not apply any sort of backwards compatibility measures. As a result you will also need to make sure that you have programmed your code to account for reading of older configurations, data, etc. More on this later."