In order to graduate from the nanodegree, you must submit all projects by the last day of the program and pass all projects once they are reviewed by a Udacity Reviewer (the review may take place after the last day of the term). Passing a project means a Udacity Reviewer has marked a project as "Meets Specifications."
If you do not submit all projects by the end of the nanodegree and also pass all projects once they are reviewed, you will receive a 4-week extension to complete any outstanding projects. You will only receive this extension once. If you do not submit and pass all projects within the 4-week extension, you will be removed from the program and lose access to the content going forward.