docs(rfd): Add update on rfd progress (#383)

Author: benbrandt

docs/rfds/session-config-options.mdx

@@ -261,3 +261,5 @@ This is a question we should discuss of how much complexity we want to introduce
 ## Revision history
 
 - 2025-10-29: Initial draft
+- 2026-01-09: Add option categories
+- 2026-01-15: Allow for category extensions

docs/updates.mdx

@@ -4,6 +4,13 @@ description: Updates and announcements about the Agent Client Protocol
 rss: true
 ---
 
+<Update label="January 15, 2025" tags={["RFD"]}>
+## Session Config Options RFD moves to Preview stage
+
+The RFD for adding more generic Session Config Options to the protocol has been moved to Preview stage. Please review the [RFD](./rfds/session-config-options) for more information on the current proposal and provide feedback before the feature is stabilized.
+
+</Update>
+
 <Update label="January 14, 2026" tags={["RFD"]}>
 ## Authentication Methods RFD moves to Draft stage