3.1 Acknowledgement of receipt 

For international applications filed online using OLF, Online Filing 2.0 or Web-Form Filing, receipt is acknowledged electronically following successful submission. The acknowledgement contains the identity of the receiving Office, the date and time of receipt, a reference or application number, a list of the files transmitted and, for online filings using OLF or Online Filing 2.0, a message digest, i.e. the message in compressed form.

The EPO as receiving Office will acknowledge receipt of a purported international application filed on paper, or by fax or using an electronic data carrier using EPO Form 1031, which will be sent by post, as a rule within four working days. In it, the EPO will explicitly confirm the receipt of each document making up the international application and each accompanying item. However, the EPO does not verify the number of sheets making up a given document. EPO Form 1031 is also sent for international applications filed using Web-Form Filing, in addition to the electronic acknowledgement of receipt generated for such applications.

The same procedure applies to international applications filed on electronic data carriers. The EPO acknowledges receipt of documents filed using the EPO Contingency Upload Service electronically in the service. An acknowledgement indicating in particular the application number, where applicable, is also sent in accordance with the provisions governing the filing of documents on paper.

Upon receipt of paper documents purporting to be an international application, the EPO as receiving Office proceeds according to GL/RO, Chapter IV, paragraph 35.

For general information on the receipt of documents at the EPO and for information on acknowledgement of receipt by fax, see GL/EPO A‑II, 3.1, which applies mutatis mutandis to international applications.