An applicant has 12 months following the filing of a provisional patent application to either convert or file a non-provisional claiming the benefit of the earlier-filed provisional patent application. After 12 months, the provisional application automatically dies or lapses. No, not quite. Under the new Patent Law Treaty provisions, the right of priority can be restored within two months of the 12-month lapse date. Great, but it is never good practice to let a provisional lapse.