releanse-notes: updating references to the rc

Author: Sam Kleinman

source/release-notes/2.4.txt

@@ -486,7 +486,7 @@ New Modular Authentication System with Support for Kerberos
 
    These features are only present in the `MongoDB Subscriber Edition
    <https://www.10gen.com/mongodb-subscriber-edition-download>`_. To
-   download 2.3 development releases of the Subscriber Edition, use
+   download the 2.4.0 release candidate the Subscriber Edition, use
    the following resources:
 
    - `Amazon Linux 6.4 <http://s3.amazonaws.com/downloads.10gen.com/linux/mongodb-linux-x86_64-subscription-amzn64-2.4.0-rc0.tgz>`_
@@ -511,7 +511,7 @@ Initial Support for Kerberos Authentication
 
 Development work on this functionality is ongoing, and additional
 related functionality is forthcoming. To use Kerberos with MongoDB as
-of the current 2.3-series release, consider the following requirements:
+of the 2.4.0 release candidate, consider the following requirements:
 
 - add users to MongoDB as with the existing authentication
   mechanism: