With some European states which are not a party to the EPC and thus not "included" in the designation "EP", the EPO has concluded so-called "extension agreements". Pursuant to such agreements and the relevant national law, it is possible for applicants to extend European patent applications and patents to extension states, where the extended patents will confer essentially the same protection as patents granted by the EPO for the current 38 member states of the European Patent Organisation. Valid extension requires firstly that the applicant submits a request for extension and pays the extension fee(s) in due time, i.e. within 31 months from the date of filing (or the earliest priority date) or six months from the date of publication of the international search report, whichever is the later. A further requirement is that, on the international filing date, the extension agreement has to be in force and the extension state must both be a PCT contracting state and be designated for a national patent in the international application. 

As to the extension of a European patent to the Republic of Montenegro (ME) following its Declaration of Independence on 3 June 2006 and before entry into force of the extension agreement on 1 March 2010, please refer to the information in the Official Journal. 

The extension agreements with Albania (AL), Croatia (HR), Latvia (LV), Lithuania (LT), North Macedonia (MK), Romania (RO), Serbia (RS) and Slovenia (SI) terminated when these states acceded to the EPC. The extension system continues to apply after the relevant termination date for all applications filed prior to the date on which the extension agreement concerned terminated.

A decision on the states for which extension is sought - and, in accordance therewith, timely payment of the extension fee(s) is due - need not be taken until the application has to enter the European phase (see points 5.8.012 ff).