3. Extension and validation states
3.1 Extension states
Between 1993 and 2009, the European Patent Organisation concluded what are known as "extension agreements" with a number of European states which had not yet acceded to the EPC at the time and were thus not "included" in the designation "EP", as well as with one which has not acceded to the EPC so far (Bosnia and Herzegovina). Under such an extension agreement and the relevant national law, it is possible for applicants to extend European patent applications and patents to the extension state concerned, where the extended patents will confer essentially the same protection as patents granted by the EPO for the member states of the European Patent Organisation. Valid extension requires firstly that the applicant submit a request for extension and pay the extension fee(s) in due time, i.e. within the period for performing the acts required for entry of an international application into the European phase or within six months of the date of publication of the international search report, whichever period expires 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.
All extension states (whether former or current) were already PCT contracting states on the date of entry into force of their respective extension agreement. Moreover, since 1 January 2004, all PCT contracting states have been automatically designated for a national and, where applicable, a regional patent.
Extension may be requested for the following European state:
–Bosnia and Herzegovina (BA) (since 1 December 2004).
The extension agreements with Albania (AL), Croatia (HR), Latvia (LV), Lithuania (LT), Montenegro (ME), North Macedonia (MK), Romania (RO), Serbia (RS) and Slovenia (SI) terminated when these states acceded to the EPC. The extension system nevertheless continues to apply for all applications filed prior to the date on which each state's particular extension agreement terminated.
In view of the time limit for paying extension fees, it is not necessary to decide whether to seek extension – or pay the extension fee due accordingly – prior to the application's entry into the European phase.