PCT Receiving Office Guidelines
Chapter XIX: Miscellaneous
Keeping of Records and Files
336. The receiving Office keeps the records relating to the international application or purported international application for at least 10 years from the international filing date or, where no international filing date is accorded, from the date of receipt of the purported application (Rule 93.1). Records, copies and files may be kept as photographic, electronic or other reproductions, provided that the reproductions are such that the obligations to keep records, copies and files under Rule 93.1 to 93.3 are met (Rule 93.4).