For international applications filed online using OLF, CMS 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 CMS, a message digest, i.e. the message in compressed form.[OJ EPO 2019, A19; ]

The EPO as receiving Office will acknowledge receipt of a purported international application filed on paper or by fax 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.[OJ EPO 2018, A45; ]

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.[]