2.2.10.How can further documents be filed? 

2.2.031After an international application has been filed, other documents may be filed in any proceedings before the EPO online or by delivery by hand, by post or by fax at the EPO filing offices. However, priority documents issued in paper form which have to be certified by the issuing authority should also be submitted to the EPO in that form to ensure the validity of the certification. For that reason, they may not be filed by fax or via the EPO web-form filing service. On the other hand, priority documents issued in electronic form are accepted only if they are digitally signed by the issuing authority and if that signature is also accepted by the EPO. Applicants filing an international application claiming the priority of an application filed with an office participating in the WIPO Digital Access Service (DAS) may request the IB to obtain a certified copy of the earlier application via DAS.²³

2.2.032There is no obligation to file a confirmation copy of subsequent documents filed by fax, but the EPO as receiving Office may require one to be submitted and will do so in particular if the applicant has submitted substitute sheets under Rule 26 PCT and/or any sheets to be incorporated by reference under Rule 20.6 PCT. In these cases, applicants are advised to submit a confirmation copy on their own initiative directly after sending the sheets concerned by fax (see point 2.2.025). If a confirmation copy is not submitted within the time limit prescribed in the invitation issued by the EPO as receiving Office, the document will be treated as not having been received.