adding versionadded
diff --git a/docs/hazmat/primitives/interfaces.rst b/docs/hazmat/primitives/interfaces.rst
index 57a8412..0c193bd 100644
--- a/docs/hazmat/primitives/interfaces.rst
+++ b/docs/hazmat/primitives/interfaces.rst
@@ -108,6 +108,8 @@
 
 .. class:: RSAPrivateKey
 
+.. versionadded:: 0.2
+
     An `RSA`_ private key.
 
     .. method:: public_key()
@@ -167,6 +169,8 @@
 
 .. class:: RSAPublicKey
 
+.. versionadded:: 0.2
+
     An `RSA`_ public key.
 
     .. attribute:: modulus