Hello,

In our company we have an admin team that looks over the entire SF organization and there are groups that have developed their own apps in the org and have their own admins for those apps. The admins in our organization have left it up to each group to decide when to move to lightning. My group's Director (of which I am an admin) is planning to migrate to Lightning. We have 3 apps in Classic that need to be migrated to Lightning. However, there are a lot of changes that we would like to make in our current apps. So, my questions to you all are-

1. What would be the right way to do it- upgrade our apps to Lighting and then make the changes or make the changes before we migrate to Lightning?  

2. When I upgrade my apps to lightning, will the pages be automatically converted to lightning pages?

Has anyone faced a similar situation? If so, I'd love to hear what your approach was?

Thank you for your inputs in advance!