If you're using a Kit, all you need to do is change your kit's version setting to Version 6. Then refresh your kit information in your WordPress plugin settings. Your version 6 kit will handle any backwards compatibility automatically. Lastly, go grab yourself a coffee with all that time you just saved.
You can either create a new Kit or upgrade an existing one. Heads up though - If you use Version 6 icons and tools, you won't be able to successfully switch back to Version 5 without removing those from your project.
If you need to switch between Web Font and SVG+JS technologies we recommend creating a different kit to switch between technologies because we've seen some delay in getting updates when using the same kit due to caching.