Breaking backwards compatiblity

[Walter Bright]

This statement is from Linus Torvalds about breaking binary compatibility:

https://lkml.org/lkml/2012/3/8/495

While I don't think we need to worry so much at the moment about breaking binary 
compatibility with new D releases, we do have a big problem with breaking source 
code compatibility.

This is why we need to have a VERY high bar for breaking changes.