Major:

- - BIP 16
- - bloom filters
- - switch to LevelDB (which is a good change I support)

Minor:

- - user agent
- - duplicate transactions check
- - pong message
- - height in coinbase
- - mempool message
- - varying length fields in version message

BIP 16 is a big change to the protocol. It requires changes all across
the codebase. Imagine that I represent scripts internally not as a
byte stream but as a data structure. Or what about the change to
version messages in bloom filters with an 1-byte optional field that
is checked by seeing if the byte exists in the byte-stream or not. So
now generic code using iterators needs to know the underlying size of
the container to know whether to parse the byte or not. Also there's
no guarantee about field lengths in Bitcoin messages for strictness
and strongly defined protocol messages.

This makes it difficult to focus on implementation when new features
are added with regularity to the protocol. It's a big investment of
time to write a good implementation.

http://libbitcoin.dyne.org/doc/

On 04/07/13 01:04, Peter Todd wrote:
> What changes do you consider to be these "3 major changes"?