New forward and backward compatibility rules for the protocols specified in ASN.1 have been adopted. These rules are simple to use and are based on the most recent X.680 Series Recommendations for ASN.1. Paragraph 12.5/Q.1400 (Recommendation published in 1993) should be replaced by the following text.
ITU-T Q.1400 ADD 1 FRENCH-1995 history
1995ITU-T Q.1400 ADD 1 FRENCH-1995 ARCHITECTURE FRAMEWORK FOR THE DEVELOPMENT OF SIGNALLING AND OAM PROTOCOLS USING OSI CONCEPTS