Where the certified copy of the priority document or, where no copy must be filed (see point 634), the application number has not yet been submitted on entry into the European phase, the applicant will be invited to furnish that copy or number within two months from the date of a notification under Rule 163(2) EPC. This time limit cannot be extended. If the priority document or the application number is not submitted within that time limit, the priority right is lost.
If a priority document has not been received from the IB (see point 630) and is missing on Patentscope but the applicant has requested the receiving Office to forward the priority document(s) to the IB or requested the IB to obtain the certified copy of the earlier application(s) from a digital library, no loss of rights will occur. In such case substantive examination may nevertheless begin, but the decision to grant will not be taken until the priority document is furnished. The applicant is informed accordingly.
Source: http://www.epo.org/applying/international/guide-for-applicants/html/e/ga_e_xiii_2.html
Date retrieved: 30 December 2018