4.1.5 Date of filing 

The filing date accorded to the application is the date the application meets the requirements of Rule 40 and is either:

(i)the date of receipt at the EPO or competent national authority or 

(ii)the date, not later than the two-month period referred to in Rule 55, on which the applicant rectifies any deficiencies. The applicant is informed of the filing date accorded to the application in this case.

Case (ii) is subject to one exception. Where the application is filed by reference to a previously filed application and the applicants fail to file the certified copy of the previously filed application within two months of the filing date as required by Rule 40(3), an invitation is sent to them to file it within two months of a communication according to Rule 55. If they file the certified copy within this two-month period, the application maintains its original filing date, provided that all other requirements for acquiring a filing date have been met.

The filing date may also change in cases where the applicant inserts missing parts of the description or missing drawings under Rule 56 (see A‑II, 5) or corrects erroneously filed parts under Rule 56a (see A‑II, 6) after the filing date.