The date of filing accorded to the application is the date the application meets the requirements of A‑II, 4.1 and is either:
Case (ii) is subject to one exception. Where the application is filed by reference to a previously filed application and the applicant fails to file the certified copy of the previously filed application within two months of the filing date as required by Rule 40(3), he is invited to file it within a period of two months from a communication according to Rule 55. If the applicant files the certified copy within this two-month period, the application maintains its original date of filing, provided that all other requirements for acquiring a date of filing have been met.
The date of filing may also change in cases where the applicant inserts parts of the description or drawings after the date of filing (see A‑II, 5).