diff --git a/doc/MediaSigning.xml b/doc/MediaSigning.xml
index 676bfc52..5f7ae48b 100644
--- a/doc/MediaSigning.xml
+++ b/doc/MediaSigning.xml
@@ -58,12 +58,6 @@
       signing feature, and also how an ONVIF client should validate the authenticity of a signed
       stream. Audio is outside of scope.</para>
   </chapter>
-  <chapter xml:id="chapter_spec_version">
-    <title>Specification version v1.0</title>
-    <para>This number should be updated when an update to the specification breaks the bitstream
-      format or when new features are added. Such features could be new ways of hashing or support
-      of more codecs.</para>
-  </chapter>
   <chapter xml:id="chapter_a3s_njq_bwb">
     <title>Normative references</title>
     <para>ITU-T Recommendation, H.264: Advanced video coding for generic audiovisual services</para>
@@ -914,7 +908,7 @@
         <itemizedlist>
           <listitem>
             <para>Tag version (1 byte)</para>
-            <para>Version = 1</para>
+            <para>Version = 2</para>
           </listitem>
           <listitem>
             <para>Specification version (3 byte)</para>
@@ -933,9 +927,18 @@
           </listitem>
           <listitem>
             <para>The UTC (8 bytes) based time represented by the number of 100-nanosecond intervals
-              since January 1, 1601 of the I-frame leading the GOP.</para>
-            <para>The timestamp value is a 64 bit parameter and the 8 bytes should be written with
+              since January 1, 1601 of the frame leading the (partial) GOP.</para>
+            <para>The start timestamp value is a 64 bit parameter and the 8 bytes should be written with
+              little endian.</para>
+          </listitem>
+          <listitem>
+            <para>Only present from tag version 2.</para>
+            <para>The UTC (8 bytes) based time represented by the number of 100-nanosecond intervals
+              since January 1, 1601 of the frame leading the upcoming (partial) GOP.</para>
+            <para>The end timestamp value is a 64 bit parameter and the 8 bytes should be written with
               little endian.</para>
+            <para>The duration of the signed (partial) GOP can now be calculated as duration =
+              "end timestamp" - "start timestamp". Note that the end timestamp is exclusive.</para>
           </listitem>
           <listitem>
             <para>GOP counter (4 bytes)</para>