incompatibility between versions should be called (at least) an issue imho...
My point was that exhaustive testing of 0.8 would never have revealed the bug in 0.7 that nobody knew about.
Unit testing to make sure the code was actually capable of operating at the protocol limits would have caught the problem had it been performed on 0.7
Indeed, the testing should have been conducted in the
three years since Bitcoin was released. It's appalling how the edge conditions were never tested.
Not sure backward compatibility is an edge case.... generally its a big deal you plan a transition for. What happened here was a rushed satoshi dice bailout with much discussion on filtering out their transactions while a real solution could be worked on.... which now leaves everyone feeling the pain instead of a single entertainment site.