Backwards-incompatible changes

• BackwardsIncompatibleChangesAfter0.7 (changes made after [1227] on May 27, 2008)
• BackwardsIncompatibleChangesAfter0.6 (changes made after [855] on October 31, 2007)
• BackwardsIncompatibleChangesAfter0.5 (changes made after [674] on August 22, 2007)
• BackwardsIncompatibleChangesBefore0.5 (changes made before [674] on August 22, 2007)