For which states may international applications be filed?
WIPO PCT Guide 5.052
Upon filing of the PCT request, the applicant will obtain automatic and all-inclusive coverage of all designations available under the PCT on the international filing date, in respect of every kind of protection available and in respect of both regional and national patents. The (automatic) designation of "EP" covers all EPC contracting states for which the PCT and the EPC are in force on the filing date of the international application.
A decision on the EPC contracting states in which protection by way of a European patent is actually being sought need not be made until the application enters the European phase (see points 5.1.008 ff). It is important to note that, if a state accedes to the EPC after the international filing date, the EPO cannot act as a designated Office for the EPC contracting state concerned and no European patent can be obtained for that state. In this respect, the date of entry into the European phase is irrelevant.
Source: http://www.epo.org/applying/international/guide-for-applicants/html/e/ga_c2_10.html
Date retrieved: 17 May 2021