2008-11-25 version 2.0.3:

  protoc
  * Enum values may now have custom options, using syntax similar to field
    options.
  * Fixed bug where .proto files which use custom options but don't actually
    define them (i.e. they import another .proto file defining the options)
    had to explicitly import descriptor.proto.
  * Adjacent string literals in .proto files will now be concatenated, like in
    C.

  C++
  * Generated message classes now have a Swap() method which efficiently swaps
    the contents of two objects.
  * All message classes now have a SpaceUsed() method which returns an estimate
    of the number of bytes of allocated memory currently owned by the object.
    This is particularly useful when you are reusing a single message object
    to improve performance but want to make sure it doesn't bloat up too large.
  * New method Message::SerializeAsString() returns a string containing the
    serialized data.  May be more convenient than calling
    SerializeToString(string*).
  * In debug mode, log error messages when string-type fields are found to
    contain bytes that are not valid UTF-8.
  * Fixed bug where a message with multiple extension ranges couldn't parse
    extensions.
  * Fixed bug where MergeFrom(const Message&) didn't do anything if invoked on
    a message that contained no fields (but possibly contained extensions).
  * Fixed ShortDebugString() to not be O(n^2).  Durr.
  * Fixed crash in TextFormat parsing if the first token in the input caused a
    tokenization error.
  * Fixed obscure bugs in zero_copy_stream_impl.cc.
  * Added support for HP C++ on Tru64.
  * Only build tests on "make check", not "make".
  * Fixed alignment issue that caused crashes when using DynamicMessage on
    64-bit Sparc machines.
  * Simplify template usage to work with MSVC 2003.
  * Work around GCC 4.3.x x86_64 compiler bug that caused crashes on startup.
    (This affected Fedora 9 in particular.)

  Java
  * New overload of mergeFrom() which parses a slice of a byte array instead
    of the whole thing.
  * New method ByteString.asReadOnlyByteBuffer() does what it sounds like.
  * Improved performance of isInitialized() when optimizing for code size.

  Python
  * Corrected ListFields() signature in Message base class to match what
    subclasses actually implement.
  * Some minor refactoring.

2008-09-29 version 2.0.2:

  General
  * License changed from Apache 2.0 to New BSD.
  * It is now possible to define custom "options", which are basically
    annotations which may be placed on definitions in a .proto file.
    For example, you might define a field option called "foo" like so:
      import "google/protobuf/descriptor.proto"
      extend google.protobuf.FieldOptions {
        optional string foo = 12345;
      }
    Then you annotate a field using the "foo" option:
      message MyMessage {
        optional int32 some_field = 1 [(foo) = "bar"]
      }
    The value of this option is then visible via the message's
    Descriptor:
      const FieldDescriptor* field =
        MyMessage::descriptor()->FindFieldByName("some_field");
      assert(field->options().GetExtension(foo) == "bar");
    This feature has been implemented and tested in C++ and Java.
    Other languages may or may not need to do extra work to support
    custom options, depending on how they construct descriptors.

  C++
  * Fixed some GCC warnings that only occur when using -pedantic.
  * Improved static initialization code, making ordering more
    predictable among other things.
  * TextFormat will no longer accept messages which contain multiple
    instances of a singular field.  Previously, the latter instance
    would overwrite the former.
  * Now works on systems that don't have hash_map.

  Java
  * Print @Override annotation in generated code where appropriate.

  Python
  * Strings now use the "unicode" type rather than the "str" type.
    String fields may still be assigned ASCII "str" values; they will
    automatically be converted.
  * Adding a property to an object representing a repeated field now
    raises an exception.  For example:
      # No longer works (and never should have).
      message.some_repeated_field.foo = 1

  Windows
  * We now build static libraries rather than DLLs by default on MSVC.
    See vsprojects/readme.txt for more information.

2008-08-15 version 2.0.1:

  protoc
  * New flags --encode and --decode can be used to convert between protobuf text
    format and binary format from the command-line.
  * New flag --descriptor_set_out can be used to write FileDescriptorProtos for
    all parsed files directly into a single output file.  This is particularly
    useful if you wish to parse .proto files from programs written in languages
    other than C++: just run protoc as a background process and have it output
    a FileDescriptorList, then parse that natively.
  * Improved error message when an enum value's name conflicts with another
    symbol defined in the enum type's scope, e.g. if two enum types declared
    in the same scope have values with the same name.  This is disallowed for
    compatibility with C++, but this wasn't clear from the error.
  * Fixed absolute output paths on Windows.
  * Allow trailing slashes in --proto_path mappings.

  C++
  * Reflection objects are now per-class rather than per-instance.  To make this
    possible, the Reflection interface had to be changed such that all methods
    take the Message instance as a parameter.  This change improves performance
    significantly in memory-bandwidth-limited use cases, since it makes the
    message objects smaller.  Note that source-incompatible interface changes
    like this will not be made again after the library leaves beta.
  * Heuristically detect sub-messages when printing unknown fields.
  * Fix static initialization ordering bug that caused crashes at startup when
    compiling on Mac with static linking.
  * Fixed TokenizerTest when compiling with -DNDEBUG on Linux.
  * Fixed incorrect definition of kint32min.
  * Fix bytes type setter to work with byte sequences with embedded NULLs.
  * Other irrelevant tweaks.

  Java
  * Fixed UnknownFieldSet's parsing of varints larger than 32 bits.
  * Fixed TextFormat's parsing of "inf" and "nan".
  * Fixed TextFormat's parsing of comments.
  * Added info to Java POM that will be required when we upload the
    package to a Maven repo.

  Python
  * MergeFrom(message) and CopyFrom(message) are now implemented.
  * SerializeToString() raises an exception if the message is missing required
    fields.
  * Code organization improvements.
  * Fixed doc comments for RpcController and RpcChannel, which had somehow been
    swapped.
  * Fixed text_format_test on Windows where floating-point exponents sometimes
    contain extra zeros.
  * Fix Python service CallMethod() implementation.

  Other
  * Improved readmes.
  * VIM syntax highlighting improvements.

2008-07-07 version 2.0.0:

  * First public release.