diff --git a/grammars/basicdoc-models b/grammars/basicdoc-models
index aeeb28b..eb11848 160000
--- a/grammars/basicdoc-models
+++ b/grammars/basicdoc-models
@@ -1 +1 @@
-Subproject commit aeeb28be19f832226c5d9361f3fbb743a4df5761
+Subproject commit eb11848fe33009cb53b98781e355399319c545c3
diff --git a/grammars/bsi.rnc b/grammars/bsi.rnc
index ecc5465..218e371 100644
--- a/grammars/bsi.rnc
+++ b/grammars/bsi.rnc
@@ -86,6 +86,6 @@ bsi-standard =
   element bsi-standard {
 attribute version { text },
   attribute type { "semantic" | "presentation" },
-    bibdata, termdocsource*, misccontainer?, boilerplate?, preface, sections+, annex*, bibliography, indexsect*
+    bibdata, termdocsource*, misccontainer?, boilerplate?, preface, sections+, annex*, bibliography, indexsect*, colophon?
   }
 
diff --git a/grammars/bsi.rng b/grammars/bsi.rng
index 7dfa31d..2b6bb3c 100644
--- a/grammars/bsi.rng
+++ b/grammars/bsi.rng
@@ -287,6 +287,9 @@
       <zeroOrMore>
         <ref name="indexsect"/>
       </zeroOrMore>
+      <optional>
+        <ref name="colophon"/>
+      </optional>
     </element>
   </define>
 </grammar>
diff --git a/grammars/isodoc.rnc b/grammars/isodoc.rnc
index d9d00e7..0bfbf95 100644
--- a/grammars/isodoc.rnc
+++ b/grammars/isodoc.rnc
@@ -468,7 +468,7 @@ standard-document =
 element standard-document {
   attribute version { text },
   attribute type { "semantic" | "presentation" },
-  bibdata, misccontainer?, boilerplate?, preface?, sections, annex*, bibliography?, indexsect*
+  bibdata, misccontainer?, boilerplate?, preface?, sections, annex*, bibliography?, indexsect*, colophon?
 }
 
 misccontainer = element metanorma-extension { AnyElement+ }
@@ -476,6 +476,9 @@ misccontainer = element metanorma-extension { AnyElement+ }
 preface =
   element preface { ( content | abstract | foreword | introduction | acknowledgements)+ }
 
+colophon =
+  element colophon { content+ }
+
 foreword =
   element foreword { Content-Section }
 
diff --git a/grammars/isodoc.rng b/grammars/isodoc.rng
index 90ad5d4..c69bf16 100644
--- a/grammars/isodoc.rng
+++ b/grammars/isodoc.rng
@@ -1578,6 +1578,9 @@
       <zeroOrMore>
         <ref name="indexsect"/>
       </zeroOrMore>
+      <optional>
+        <ref name="colophon"/>
+      </optional>
     </element>
   </define>
   <define name="misccontainer">
@@ -1600,6 +1603,13 @@
       </oneOrMore>
     </element>
   </define>
+  <define name="colophon">
+    <element name="colophon">
+      <oneOrMore>
+        <ref name="content"/>
+      </oneOrMore>
+    </element>
+  </define>
   <define name="foreword">
     <element name="foreword">
       <ref name="Content-Section"/>
diff --git a/grammars/relaton-models b/grammars/relaton-models
index cca170c..d7115ee 160000
--- a/grammars/relaton-models
+++ b/grammars/relaton-models
@@ -1 +1 @@
-Subproject commit cca170ccf935d89697282df31bbdb8d1ef2290c6
+Subproject commit d7115ee43416a2d3bd0b050cda687504282f247e