Migration from legacy addon to WebExtensions via auto-update

Hello, community,

I have an unlisted legacy addon, and it worked with updates nicely via the em:updateURL tag.
Now I ported it to WebExtensions, and I want to replace the legacy version with this new one.

  1. I’m planning to provide a link to the new version in my update.rdf file - will that work?
  2. Do I need to have the same addon ID, as the legacy addon have? Will the update work, if I choose another ID for my WebExt replacement?