Where the priority of an earlier application is claimed for a Euro-PCT application, the IB sends a copy of the priority document to the EPO if the IB received the priority document from the receiving Office or directly from the applicant or was able to retrieve it from a digital library. As a rule the applicant should file a copy with the receiving Office or the IB or request the IB that the copy be retrieved from a digital library within 16 months from the (earliest) priority date (see point 143).

If during the international phase the applicant did not furnish the priority document or, where no such document must be furnished, the number of the application from which priority is claimed, he may provide the priority document or that number upon entry into the European phase. 

A priority document may be filed in electronic form with the EPO only if it is digitally signed by the issuing authority and the signature is accepted by the EPO. A priority document cannot be filed by fax. 

The application number of a priority application must always be available to the EPO as designated/elected Office. This number is, if known at the time of filing the application, to be provided in Box VI of the PCT request form.

In the cases listed below, the EPO as designated/elected Office will include a copy of the priority application free of charge in the file of a Euro-PCT application even without having received a copy from the IB. The applicant will be informed of this inclusion unless the previous application is a European application or an international application filed with the EPO as receiving Office. This service is provided on condition that the applicant has informed the EPO of the application number and only if the priority application is: