You can, but you need to design and plan for it. State depended on by code is usually the biggest problem; you need to design your code and rollout process to w

You can, but you need to design and plan for it. State depended on by code is usually the biggest problem; you need to design your code and rollout process to work with both old and new state. For example, if you add a column to a database table, then both the old code should be able to work seamlessly both with and without this column. In practice, this would mean not making the column a required one, unless you can invent some kind of neutral default value.