deprecationwarning for OpenSSL < 1.0.1 as upstream has dropped support
diff --git a/src/cryptography/hazmat/bindings/openssl/binding.py b/src/cryptography/hazmat/bindings/openssl/binding.py
index 07b6b9a..8e41943 100644
--- a/src/cryptography/hazmat/bindings/openssl/binding.py
+++ b/src/cryptography/hazmat/bindings/openssl/binding.py
@@ -8,6 +8,7 @@
import os
import threading
import types
+import warnings
from cryptography.exceptions import InternalError
from cryptography.hazmat.bindings._openssl import ffi, lib
@@ -180,3 +181,11 @@
# condition registering the OpenSSL locks. On Python 3.4+ the import lock
# is per module so this approach will not work.
Binding.init_static_locks()
+
+if Binding.lib.SSLeay() < 0x10001000:
+ warnings.warn(
+ "OpenSSL versions less than 1.0.1 are no longer supported by the "
+ "OpenSSL project, please upgrade. A future version of cryptography "
+ "will drop support for these versions.",
+ DeprecationWarning
+ )