V6.27 to V7 Bench update error

https://urllib3.readthedocs.org/en/latest/security.html#snimissingwarning.
  SNIMissingWarning
/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:122: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. You can upgrade to a newer version of Python to solve this. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#insecureplatformwarning.
  InsecurePlatformWarning
Requirement already up-to-date: pip in ./env/lib/python2.7/site-packages
/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:318: SNIMissingWarning: An HTTPS request has been made, but the SNI (Subject Name Indication) extension to TLS is not available on this platform. This may cause the server to present an incorrect TLS certificate, which can cause validation failures. You can upgrade to a newer version of Python to solve this. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#snimissingwarning.
  SNIMissingWarning
/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:122: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. You can upgrade to a newer version of Python to solve this. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#insecureplatformwarning.
  InsecurePlatformWarning
/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:318: SNIMissingWarning: An HTTPS request has been made, but the SNI (Subject Name Indication) extension to TLS is not available on this platform. This may cause the server to present an incorrect TLS certificate, which can cause validation failures. You can upgrade to a newer version of Python to solve this. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#snimissingwarning.
  SNIMissingWarning
/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:122: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. You can upgrade to a newer version of Python to solve this. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#insecureplatformwarning.
  InsecurePlatformWarning
Command "/home/frappe/frappe-bench/env/bin/python -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-v64mf4/cryptography/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-0CRt9e-record/install-record.txt --single-version-externally-managed --compile --install-headers /home/frappe/frappe-bench/env/include/site/python2.7/cryptography" failed with error code 1 in /tmp/pip-build-v64mf4/cryptography/
Traceback (most recent call last):
  File "/usr/local/bin/bench", line 9, in <module>
    load_entry_point('bench==2.1.0', 'console_scripts', 'bench')()
  File "/home/frappe/bench-repo/bench/cli.py", line 40, in cli
    bench_command()
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 716, in __call__
    return self.main(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 696, in main
    rv = self.invoke(ctx)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 1060, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 889, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 534, in invoke
    return callback(*args, **kwargs)
  File "/home/frappe/bench-repo/bench/commands/update.py", line 60, in update
    _update(pull, patch, build, bench, auto, restart_supervisor, requirements, no_backup, upgrade, force=force)
  File "/home/frappe/bench-repo/bench/commands/update.py", line 79, in _update
    update_requirements(bench_path=bench_path)
  File "/home/frappe/bench-repo/bench/utils.py", line 378, in update_requirements
    install_requirements(pip, req_file)
  File "/home/frappe/bench-repo/bench/utils.py", line 382, in install_requirements
    exec_cmd("{pip} install -q -r {req_file}".format(pip=pip, req_file=req_file))
  File "/home/frappe/bench-repo/bench/utils.py", line 130, in exec_cmd
    raise CommandFailedError(cmd)
bench.utils.CommandFailedError: ./env/bin/pip install -q -r ./apps/frappe/requirements.txt

Please help me my data gone. It’s show INTERNAL SERVER ERROR on browser

If you’re on Ubuntu run:

sudo apt-get install libffi-dev libssl-dev

If you’re on CentOS run:

sudo yum install libffi-devel openssl-devel

If you’re on macOS run:

 brew install openssl