This version adds a new optional Rust-based backend. This is turned off by default so shouldn't affect users. The new backend uses the tibs library, which is by the same author as bitstring and should allow some nice optimisations as the whole stack can work together.
For now the Rust backend is about the same speed as the C backend (which uses bitarray) so there are no real advantages to use it yet. If you do want to try it then you'll need to set the BITSTRING_USE_RUST_CORE environment variable.
BITSTRING_USE_RUST_CORE=1 python your_script.py
You can check which backend is being used using bitstring.options.using_rust_core which should be False unless you've enabled it as detailed above.
The plan is to remove the C backend in version 5, which will allow lots of code simplifications and further performance improvements.
The tibs dependency is a bit experimental and difficult to test on every possible platform. If you experience any issues with installation then please file a bug report.
The only other change is explicit support for Python 3.14.