A Product Increment is the outcome of an iteration (Sprint).

In SCRUM the most important question concerning a specific Product Increment is “What does done exactly mean?”.

The Increment is the set of all items of the Product Backlog which have been completed in a Sprint.

The Sprint ends with an Increment which is in useable condition and meets the Definition of “Done”.

Each Increment will be thoroughly tested, ensuring that the product will work after release.

It must be in useable condition regardless of whether the Product Owner decides to actually release it.