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.