The most recent count of completed story points in an iteration is the team's velocity. The number of story points completed in an iteration will change over time. Consequently, the team's velocity also changes. If the team's velocity increases, more work can be done in each iteration. If the team's velocity decreases, less work can be done in each iteration.

As the team progresses through the project, the team's understanding of the problem is improved. Customers will add new stories and remove others. Programmers may need to change story estimates. Consequently, the release plan should be revisited periodically (every few iterations or as needed).

Using the most recent velocity, the latest story estimates, and the customer's most recent view of priority, a new release plan is established.

Once the plan is updated, it is critical that the whole team be aware of it. This is usually really easy as the whole team was involved in the revision of the release plan. The plan will show the team the progress they are making (morale), and they will have a clear understanding of the new target they are shooting for (team cohesion).The plan must be realistic and alive.