Onboarding experience for redesigned apps

Does anyone have thoughts or good examples (or even white papers) about how to approach onboarding experience for complete app redesign? The two considerations that we are trying to balance is help existing users with getting used to the new UI and helping highlight the brand.

The Current approach being considered: 1) Traditional 3 screens (skippable) of the the updated features -- this seems like it would help with customer desire for "branding" 2) Hints when app gets first loaded that highlight the changes in navigation and most used features -- I think this will probably help most with actual onboarding and ramp up to the new UI

Additionally, are you aware of a mixed approach where new downloads will get one onboarding experience while existing app updates get a different more experienced user onboarding?