diff --git a/src/colophon.adoc b/src/colophon.adoc
index e098f57f8..b7b52af1c 100644
--- a/src/colophon.adoc
+++ b/src/colophon.adoc
@@ -71,6 +71,7 @@ The changes in this version of the document include:
 
 * The inclusion of all ratified extensions through March 2024.
 * The draft Zam extension has been removed, in favor of the definition of a misaligned atomicity granule PMA.
+* The concept of vacant memory regions has been superseded by inaccessible memory or I/O regions.
 
 [.big]*_Preface to Document Version 20191213-Base-Ratified_*
 
diff --git a/src/priv-preface.adoc b/src/priv-preface.adoc
index 8e97ecd57..ba36ebbc9 100644
--- a/src/priv-preface.adoc
+++ b/src/priv-preface.adoc
@@ -62,11 +62,10 @@ _Draft_ +
 *Ratified*
 |===
 
-The following changes have been made since version 1.13, which, while
-not strictly backwards compatible, are not anticipated to cause software
-portability problems in practice:
+The changes in this version of the document include:
 
 * The inclusion of all ratified extensions through March 2024.
+* The concept of vacant memory regions has been superseded by inaccessible memory or I/O regions.
 
 [.big]*_Preface to Version 20240213_*