I rebuilt a web app to replace a version that we have been using for the last 3-4 years. We have a few thousand clients and a few hundred active users per day. The functionality is basically the same. The new version is a little bit faster with a few enhancement features and there are a lot of behind the scenes changes that the clients will never see. The UI is quite different but ultimately much easier to use and navigate. How should I go about having our clients stop using the old system and start using the new one? I am currently putting together a video that will play on the web site as well as within the app. The video will go through the pages and focus on some key changes. I was also thinking about an intro page that will display once the user logs in and explains some of the features.