Agile and Waterfall Approach, does a hybrid methodology exist?

Our project is a hybrid because while the software development team used a Scrum approach, the rest of the teams used a more typical predictive approach. Add to that the fact that senior management wanted typical predictive outcome indicators: How much is done? When will you be done?

We delivered products to the general public and to the internal staff. We did a better job of involving the targeted public at each sprint, than we did with our internal staff.

Now that we are live, employees have become de jure testers. Employees struggle to keep up with the two-week sprint releases, being used to quarterly releases.