What are the IPC editions?
(see also paragraphs 8 to 10bis and 42 of the Guide to the IPC) The IPC is periodically revised for improving the system and for reflecting technical developments in its contents. Since its first edition, revision of the IPC has been made, for many years, in five-year intervals. The first edition of the Classification was in force from September 1, 1968, to June 30, 1974, the second from July 1, 1974, to December 31, 1979, the third from January 1, 1980, to December 31, 1984, the fourth from January 1, 1985, to December 31, 1989, the fifth from January 1, 1990, to December 31, 1994, the sixth from January 1, 1995, to December 31, 1999, the seventh from January 1, 2000, to December 31, 2005, and the eighth from January 1, 2006, to December 31, 2008. With the entry into force of the reformed IPC, on January 1, 2006, this revision policy has changed. The core level of the IPC is revised every three years. However, longer time intervals are possible as well. For the advanced level, revised
