New libosmium features since 2.20.0 (September 2023):

• C++17/C++20 compilation support
• LZ4 compression support for PBF files (faster than ZLIB)
• Reduced dependencies (uses std::variant instead of boost::variant when available)
• Memory efficiency improvements in area assembly
• Removed deprecated sparsehash index support
• Reduced dependencies (less reliance on Boost libraries)