diff --git a/src/openssl.hxx b/src/openssl.hxx
index 39e4326..fb4da80 100644
--- a/src/openssl.hxx
+++ b/src/openssl.hxx
@@ -24,13 +24,21 @@
 #ifndef OPENSSL_VERSION_NUMBER
 #  error OpenSSL Version Number not Found
 #elif OPENSSL_VERSION_NUMBER < 0x00908000L
-#  warning OpenSSL older than 0.8 detected
+#  ifdef ALLOW_SSL_OLDER_THAN_0_8
+#    warning OpenSSL older than 0.8 detected
+#  else
+#    error OpenSSL older than 0.8 detected
+#  endif
 #  define OPENSSL_0_7
 #  define V0_CONST
 #  define CV_STACK
 #  define CV_X509
 #elif OPENSSL_VERSION_NUMBER < 0x10000000L
-#  warning OpenSSL 0.8 detected
+#  ifdef ALLOW_SSL_0_8
+#    warning OpenSSL 0.8 detected
+#  else
+#    error OpenSSL 0.8 detected
+#  endif
 #  define OPENSSL_0_8
 #  define V0_CONST const
 #  define CV_STACK