I created a brief summary of enhancements/changes to property_tree which were proposed so far. 1. Make path a class in its own right and overload / (division) operator to concatenate path objects efficiently. This removes need for ugly default separator, and half of the get/put overloads. It also boosts performance (no more string operations on path), and IMHO will generally improve interface of the library. Most importantly, it largely does maintain compatibility with existing interface. 2. Split Traits into smaller policy classes. For example KeyPolicy and DataPolicy. Indeed, these two are mostly orthogonal, and it should be possible to replace one without touching the other. 3. Allow use of other data types as keys/paths (for example a vector of ints). Initial support is in the library, but key is still required to support string-like interface. 4. Add possibility to disable indexed lookup, if not required 5. Add possibility to specify names of "special" keys in parsers (<xmlattr>, <xmlcomment> etc.). Add whitespace-handling flags to XML reader. 6. Add "set" function. "set" will work in a similar fashion to put, except that it will always replace existing key if it exists. Extra boolean parameter to put functions will be gone. Alternative approach is to replace bool parameter to put with enum to improve readability. 7. Add "del" function. Del will erase existing keys from the tree, while presenting get/put/set style interface. This is clearly missing, although not immediately obvious. 8. Add support for array-style indexing in paths. This will probably work well with #1. 9. Add support for serialization of ptree objects 10. Add possibility to iterate over the whole tree in one go 11. Use multi_index internally for indexing 12. Make get/put functions freestanding 13. Add more docs on customizing key/data types. 14. Improve docs grammar/style in places. Break large index into smaller files. Additionally there were proposals to use runtime polymorphism to distinguish between leaf and branch nodes. I think this idea strays so far from current implementation/interface of the library, that it is not feasible to do. I hope this will serve as a basis for continued discussion. Best regards, Marcin