Preferred way to rewrite a guide

Is there a preferred way to rewrite a guide/how-to? I have written this guide: HOW TO: Minimal Ubuntu 16.04 with Kodi, Steam & EmulationStation. I have now found a better way to integrate Kodi, Steam and emulators compared to the one described in my guide. However, this new approach would mean that I need to rewrite large sections.

I would like to preserve the old guide for reference, but I do not want to add new sections to the old guide because the readability would suffer. Also, some of the post in the thread still applies to the new guide.

Right now I am thinking about these solutions:

  • Create a new thread for the new guide
  • Use strike-through to show what sections no longer apply in the old guide and add the new sections
  • Add a post in my old thread with the new guide and link to this new guide in the beginning of the thread

What would be the best solution? And how are these things usually done?