diff --git a/src/general-info/release-21b.txt b/src/general-info/release-21b.txt
index 8bc6bf7278f60b111bd31200abc2ee65e3037919..7489d64110406c3d030f67d325a22e4724309796 100644
--- a/src/general-info/release-21b.txt
+++ b/src/general-info/release-21b.txt
@@ -58,6 +58,7 @@ New in this release:
     * For linux, darwin, and solaris/sparc, the binding stack and
       control stack are now mapped into memory whereever the OS wishes
       to place them instead of being mapped into a fixed location.
+      This is indicated by new feature :relocatable-stacks.
 
   * ANSI compliance fixes:
     * PATHNAME-MATCH-P did not accept search-lists.