Update OpenSSL backend docs.
diff --git a/docs/hazmat/backends/openssl.rst b/docs/hazmat/backends/openssl.rst
index b48e502..6c3d875 100644
--- a/docs/hazmat/backends/openssl.rst
+++ b/docs/hazmat/backends/openssl.rst
@@ -16,12 +16,13 @@
     * :class:`~cryptography.hazmat.backends.interfaces.CipherBackend`
     * :class:`~cryptography.hazmat.backends.interfaces.CMACBackend`
     * :class:`~cryptography.hazmat.backends.interfaces.DSABackend`
+    * :class:`~cryptography.hazmat.backends.interfaces.EllipticCurveBackend`
     * :class:`~cryptography.hazmat.backends.interfaces.HashBackend`
     * :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`
     * :class:`~cryptography.hazmat.backends.interfaces.PBKDF2HMACBackend`
-    * :class:`~cryptography.hazmat.backends.interfaces.PKCS8SerializationBackend`
     * :class:`~cryptography.hazmat.backends.interfaces.RSABackend`
-    * :class:`~cryptography.hazmat.backends.interfaces.TraditionalOpenSSLSerializationBackend`
+    * :class:`~cryptography.hazmat.backends.interfaces.PEMSerializationBackend`
+    * :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
 
     It also exposes the following: