Answer:
hide all new functionality under feature toggles
Explanation:
The best way to accomplish this would be to hide all new functionality under feature toggles. This would allow you to implement the new features without actually releasing them. They would be hidden so that the developers can quickly activate individual new features as they wish. This helps with individually stress testing each feature to make sure that they are working perfectly before release. Once a feature has been thoroughly tested and works as intended without any bugs then it can be added as a release feature.