Heroku 24 Upgrade for Rails Web App

I'm looking to upgrade my Ruby on Rails web application hosted on Heroku from version 20 to 24. The project involves not just a platform update but also upgrading dependencies and libraries that the application relies on. The objective is to do the minimal upgrade so the platform functions in the new Heroku. I will share the Gemfile and Gemfile.lock and you will guide me in upgrading.

Ideal Skills and Experience:
- Proficient in Ruby on Rails
- Extensive experience with Heroku
- Knowledgeable in updating dependencies and libraries
- Familiarity with troubleshooting during platform upgrades
- Able to ensure application performance post-upgrade