sslutil: properly detect which TLS versions are supported by the ssl module For the record, I contacted the CPython developers to remark that unconditionally defining ssl.PROTOCOL_TLSv1_1 / ssl.PROTOCOL_TLSv1_2 is problematic: https://github.com/python/cpython/commit/6e8cda91d92da72800d891b2fc2073ecbc134d98#r39569316