Certbot: Certbot 使用旧版本的 Python

大家好，即使有最新版本的 Pip (9.0.1) 可用，Ubuntu 14.04 上的 Certbot 也使用旧版本的 Pip (8.0.3)。 我无法成功运行$certbot-auto renew 命令，因为它给出了InsecurePlatformWarning警告。 我可以解决这个问题吗？ 在下面我粘贴了所有输出：

Command "/home/wolthuis/.local/share/letsencrypt/bin/python2.7 -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-Txn1F9/cryptography/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('
', '
'), __file__, 'exec'))" install --record /tmp/pip-igOc6P-record/install-record.txt --single-version-externally-managed --compile --install-headers /home/wolthuis/.local/share/letsencrypt/include/site/python2.7/cryptography" failed with error code 1 in /tmp/pip-build-Txn1F9/cryptography
/home/wolthuis/.local/share/letsencrypt/local/lib/python2.7/site-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:120: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#insecureplatformwarning.
  InsecurePlatformWarning
You are using pip version 8.0.3, however version 9.0.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
=====================================================

Certbot has problem setting up the virtual environment.

Based on your pip output, the problem can likely be fixed by 
increasing the available memory.

Consult https://certbot.eff.org/docs/install.html#problems-with-python-virtual-environment
for possible solutions.
You may also find some support resources at https://certbot.eff.org/support/ .