Before revision: For example: M1.5, introduced by Opel in 1989 M1.5.2, 1991 M1.5.4, 1994 M1.5.5, 1997 The M2.3 und M2.3.2 (used by Audi/VW) appears long before 1997.
After revision: For example: M1.5, introduced by Opel in 1988 M1.5.2, 1991 M1.5.4, 1994 M1.5.5, 1997 The M2.3 und M2.3.2 (used by Audi/VW) appears long before 1997.