A copy of the previous application from which priority is claimed (priority document) must be filed before the end of the sixteenth month after the date of priority. Priority documents may be filed in paper form or electronically using OLF or CMS, provided the latter are in an accepted document format, have been digitally signed by the issuing authority and the signature is accepted by the EPO.

Four potential deficiencies exist with regard to the priority claim, namely:[Art. 90(4); Art. 90(5); ]

The declaration of priority should preferably be made on filing, but can be made up to 16 months from the earliest priority date claimed. That is to say, items (i)-(iii) mentioned in A‑III, 6.5 can be supplied up to 16 months after the earliest claimed priority date.

The Receiving Section need not examine the content of the priority document. However, where it is obvious, e.g. from the title of the document, that the document relates to subject-matter quite different from that of the application, the applicant should be informed that it appears that the document filed is not the relevant document.

Applications giving rise to a right of priority referred to in A‑III, 6.1(i) are those filed at industrial property offices:

(a)of or acting for states party to the Paris Convention for the Protection of Industrial Property, [Art. 87(1); ]