What about MySQLdb? That&#x27;s the main extension module that has been keeping me on Python 2 for server-side software. That, plus a lack of perceived upside to CPython 3, which is still an interpreter with a GIL after all. PyPy 3 might be compelling if it can run MySQLdb or a bug-compatible replacement. True, PyPy still has a GIL, but at least it also has a JIT compiler.