Complex sentence: The standard separator in Germany was the dot (DIN 1355, DIN 5008) until 1995, when the standards changed it to be the colon, in the interest of compatibility with ISO 8601.
Split into simpler sentences: The standard separator in Germany (as laid down in DIN 1355, DIN 5008) was the dot. In 1995 this was changed to the colon in the interest of compatibility with ISO 8601.