1.3 Filing of documents subsequent to the application 

Documents subsequent to the international application may be filed with the EPO as receiving Office on paper or electronically; see GL/PCT‑EPO A‑II, 1.2.

In the international phase, priority documents and authorisations may not be filed with the EPO as receiving Office by fax or Web-Form Filing. Priority documents may be filed electronically using OLF or Online Filing 2.0, provided they have been digitally signed by the issuing authority and the signature is accepted by the EPO. Priority documents may also be filed with the IB using ePCT.

If a document subsequent to the international application is filed by fax, there is no need to submit a confirmation copy unless the receiving Office invites the applicant to submit one (Form PCT/RO/141). It might do so particularly for substitute sheets under Rule 26 and sheets to be incorporated by reference under Rule 20.6. For such sheets, applicants are therefore advised to submit a confirmation copy on their own initiative directly after sending them by fax. If a confirmation copy is not submitted within the time limit prescribed in the invitation issued by the receiving Office, the document will be treated as not having been received (Form PCT/RO/149).