diff --git a/lib/metanorma/iec/basicdoc.rng b/lib/metanorma/iec/basicdoc.rng
index 86214c5b..9595a390 100644
--- a/lib/metanorma/iec/basicdoc.rng
+++ b/lib/metanorma/iec/basicdoc.rng
@@ -914,44 +914,47 @@
   -->
   <define name="image">
     <element name="image">
-      <attribute name="id">
-        <data type="ID"/>
+      <ref name="Image"/>
+    </element>
+  </define>
+  <define name="Image">
+    <attribute name="id">
+      <data type="ID"/>
+    </attribute>
+    <attribute name="src">
+      <data type="anyURI"/>
+    </attribute>
+    <attribute name="mimetype"/>
+    <optional>
+      <attribute name="filename"/>
+    </optional>
+    <optional>
+      <attribute name="width">
+        <choice>
+          <data type="int"/>
+          <value>auto</value>
+        </choice>
       </attribute>
-      <attribute name="src">
+    </optional>
+    <optional>
+      <attribute name="height">
+        <choice>
+          <data type="int"/>
+          <value>auto</value>
+        </choice>
+      </attribute>
+    </optional>
+    <optional>
+      <attribute name="alt"/>
+    </optional>
+    <optional>
+      <attribute name="title"/>
+    </optional>
+    <optional>
+      <attribute name="longdesc">
         <data type="anyURI"/>
       </attribute>
-      <attribute name="mimetype"/>
-      <optional>
-        <attribute name="filename"/>
-      </optional>
-      <optional>
-        <attribute name="width">
-          <choice>
-            <data type="int"/>
-            <value>auto</value>
-          </choice>
-        </attribute>
-      </optional>
-      <optional>
-        <attribute name="height">
-          <choice>
-            <data type="int"/>
-            <value>auto</value>
-          </choice>
-        </attribute>
-      </optional>
-      <optional>
-        <attribute name="alt"/>
-      </optional>
-      <optional>
-        <attribute name="title"/>
-      </optional>
-      <optional>
-        <attribute name="longdesc">
-          <data type="anyURI"/>
-        </attribute>
-      </optional>
-    </element>
+    </optional>
   </define>
   <define name="video">
     <element name="video">
diff --git a/lib/metanorma/iec/biblio.rng b/lib/metanorma/iec/biblio.rng
index ef420e46..398a4aeb 100644
--- a/lib/metanorma/iec/biblio.rng
+++ b/lib/metanorma/iec/biblio.rng
@@ -348,6 +348,9 @@
       <zeroOrMore>
         <ref name="contact"/>
       </zeroOrMore>
+      <optional>
+        <ref name="logo"/>
+      </optional>
     </element>
   </define>
   <define name="orgname">
@@ -366,6 +369,11 @@
       </choice>
     </element>
   </define>
+  <define name="logo">
+    <element name="logo">
+      <ref name="image"/>
+    </element>
+  </define>
   <define name="NameWithVariants">
     <element name="primary">
       <ref name="LocalizedString"/>
diff --git a/lib/metanorma/iec/isodoc.rng b/lib/metanorma/iec/isodoc.rng
index 77bd8677..bc0d67cc 100644
--- a/lib/metanorma/iec/isodoc.rng
+++ b/lib/metanorma/iec/isodoc.rng
@@ -17,7 +17,7 @@
   these elements; we just want one namespace for any child grammars
   of this.
 -->
-<!-- VERSION v1.2.7 -->
+<!-- VERSION v1.2.8 -->
 <grammar xmlns:a="http://relaxng.org/ns/compatibility/annotations/1.0" xmlns="http://relaxng.org/ns/structure/1.0" datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
   <include href="reqt.rng"/>
   <include href="basicdoc.rng">
@@ -1408,6 +1408,9 @@
       <optional>
         <attribute name="number"/>
       </optional>
+      <optional>
+        <attribute name="branch-number"/>
+      </optional>
       <optional>
         <attribute name="obligation">
           <choice>
@@ -1631,6 +1634,9 @@
     <optional>
       <attribute name="number"/>
     </optional>
+    <optional>
+      <attribute name="branch-number"/>
+    </optional>
     <optional>
       <attribute name="type"/>
     </optional>
@@ -1682,6 +1688,9 @@
     <optional>
       <attribute name="number"/>
     </optional>
+    <optional>
+      <attribute name="branch-number"/>
+    </optional>
     <optional>
       <ref name="section-title"/>
     </optional>
@@ -1779,6 +1788,9 @@
       <optional>
         <attribute name="number"/>
       </optional>
+      <optional>
+        <attribute name="branch-number"/>
+      </optional>
       <optional>
         <attribute name="obligation">
           <choice>
diff --git a/lib/metanorma/iec/isostandard.rng b/lib/metanorma/iec/isostandard.rng
index ae5c523e..91fbad1c 100644
--- a/lib/metanorma/iec/isostandard.rng
+++ b/lib/metanorma/iec/isostandard.rng
@@ -220,6 +220,9 @@
       <optional>
         <attribute name="number"/>
       </optional>
+      <optional>
+        <attribute name="branch-number"/>
+      </optional>
       <optional>
         <attribute name="type"/>
       </optional>
diff --git a/lib/metanorma/iec/version.rb b/lib/metanorma/iec/version.rb
index cf274540..b1cea12e 100644
--- a/lib/metanorma/iec/version.rb
+++ b/lib/metanorma/iec/version.rb
@@ -1,6 +1,6 @@
 module Metanorma
   module Iec
-    VERSION = "2.3.3".freeze
+    VERSION = "2.3.4".freeze
   end
 end
 
diff --git a/metanorma-iec.gemspec b/metanorma-iec.gemspec
index 2092d31c..ab802bd4 100644
--- a/metanorma-iec.gemspec
+++ b/metanorma-iec.gemspec
@@ -30,7 +30,7 @@ Gem::Specification.new do |spec|
   spec.test_files    = `git ls-files -- {spec}/*`.split("\n")
   spec.required_ruby_version = Gem::Requirement.new(">= 2.7.0")
 
-  spec.add_dependency "metanorma-iso", "~> 2.5.2"
+  spec.add_dependency "metanorma-iso", "~> 2.5.4"
   spec.add_dependency "pubid-iec"
   spec.add_dependency "ruby-jing"