add changelog entry for 0.9.8/1.0.0 deprecation
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 7474906..a882d26 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -17,6 +17,10 @@
   * :class:`~cryptography.x509.CertificateIssuer`
   * :class:`~cryptography.x509.CRLReason`
   * :class:`~cryptography.x509.InvalidityDate`
+* Deprecated support for OpenSSL 0.9.8 and 1.0.0. At this time there is no time
+  table for actually dropping support, however we strongly encourage all users
+  to upgrade, as those versions no longer receives support from the OpenSSL
+  project.
 * The :class:`~cryptography.x509.Certificate` class now has
   :attr:`~cryptography.x509.Certificate.signature` and
   :attr:`~cryptography.x509.Certificate.tbs_certificate_bytes` attributes.