At least in C++11, std::multimap is required to be stable for elements with the same key. However, serializing and then deserializing a multimap with Boost.Serialization can change the order of elements with the same key to be different than their order in the input multimap. Would it be possible to change multimap deserialization (since serialization appears to preserve the order already) to ensure that the output multimap exactly matches the input one? Thank you. -- Jeremiah Willcock