diff --git a/spec/profiles/ttml2-full.xml b/spec/profiles/ttml2-full.xml
index 61a0c8607..017b2b587 100644
--- a/spec/profiles/ttml2-full.xml
+++ b/spec/profiles/ttml2-full.xml
@@ -132,6 +132,7 @@
     <feature value="required">#length-pixel</feature>
     <feature value="required">#length-positive</feature>
     <feature value="required">#length-real</feature>
+    <feature value="required" extends="#length-real">#length-real-version-2</feature>
     <feature value="required">#length-root-container-relative</feature>
     <feature value="required" extends="#length">#length-version-2</feature>
     <feature value="required">#letterSpacing</feature>
diff --git a/spec/profiles/ttml2-presentation.xml b/spec/profiles/ttml2-presentation.xml
index 6e942073c..3d2f8997e 100644
--- a/spec/profiles/ttml2-presentation.xml
+++ b/spec/profiles/ttml2-presentation.xml
@@ -141,6 +141,7 @@
     <feature value="optional">#length-pixel</feature>
     <feature value="optional">#length-positive</feature>
     <feature value="optional">#length-real</feature>
+    <feature value="optional" extends="#length-real">#length-real-version-2</feature>
     <feature value="optional">#length-root-container-relative</feature>
     <feature value="optional" extends="#length">#length-version-2</feature>
     <feature value="optional">#letterSpacing</feature>
diff --git a/spec/profiles/ttml2-transformation.xml b/spec/profiles/ttml2-transformation.xml
index 3d2784132..b63b0d391 100644
--- a/spec/profiles/ttml2-transformation.xml
+++ b/spec/profiles/ttml2-transformation.xml
@@ -141,6 +141,7 @@
     <feature value="optional">#length-pixel</feature>
     <feature value="optional">#length-positive</feature>
     <feature value="optional">#length-real</feature>
+    <feature value="optional" extends="#length-real">#length-real-version-2</feature>
     <feature value="optional">#length-root-container-relative</feature>
     <feature value="optional" extends="#length">#length-version-2</feature>
     <feature value="optional">#letterSpacing</feature>
diff --git a/spec/ttml2.xml b/spec/ttml2.xml
index 3b5d452aa..3efc01826 100644
--- a/spec/ttml2.xml
+++ b/spec/ttml2.xml
@@ -15616,6 +15616,7 @@ subset of the set of named colors specified by <bibref ref="svg11"/>, &sect;4.2.
 
 non-negative-real
   : <loc href="#style-value-digit">&lt;digit&gt;</loc>* "." <loc href="#style-value-digit">&lt;digit&gt;</loc>+
+  | <loc href="#style-value-digit">&lt;digit&gt;</loc>+ "."
 </eg>
 </td>
 </tr>
@@ -21471,6 +21472,20 @@ feature if it supports the <code>#length-positive</code> feature as defined by <
 <p>A TTML content processor supports the <code>#length-real</code>
 feature if it supports the <code>#length-real</code> feature as defined by <bibref ref="ttml1"/>, &sect;D.1.50.</p>
 </div3>
+<div3 id="feature-length-real-version-2">
+<head>#length-real-version-2</head>
+<p>A TTML <loc href="#terms-transformation-processor">transformation processor</loc> supports the
+<code>#length-real-version-2</code> feature if it recognizes and is capable of
+transforming the syntax and semantics of real values of the <loc href="#style-value-length">&lt;length&gt;</loc> style value
+expression that include all values of the <code>non-negative-real</code> non-terminal expression defined by
+<code><loc href="#style-value-non-negative-number">&lt;non-negative-number&gt;</loc></code>.</p>
+<p>A TTML <loc href="#terms-presentation-processor">presentation processor</loc> supports the <code>#length-real-version-2</code>
+feature if it implements presentation semantic support for values of the <loc href="#style-value-length">&lt;length&gt;</loc> style value
+expression as described above.</p>
+<p>The <code>#length-real-version-2</code> feature is a syntactic extension of the <code>#length-real</code> feature.</p>
+<p>It is an error for a content profile to require or permit use of the <code>#length-real-version-2</code> feature but prohibit use of the
+<loc href="#feature-length-real"><code>#length-real</code></loc> feature.</p>
+</div3>
 <div3 id="feature-length-root-container-relative">
 <head>#length-root-container-relative</head>
 <p>A TTML <loc href="#terms-transformation-processor">transformation processor</loc> supports the
@@ -21490,13 +21505,15 @@ expression.
 <p>A TTML processor supports the <code>#length-version-2</code> feature if it supports the following features:</p>
 <ulist>
 <item><p><loc href="#feature-length"><code>#length</code></loc></p></item>
+<item><p><loc href="#feature-length-real-version-2"><code>#length-real-version-2</code></loc></p></item>
 <item><p><loc href="#feature-length-root-container-relative"><code>#length-root-container-relative</code></loc></p></item>
 </ulist>
 <p>The <code>#length-version-2</code> feature is a syntactic and semantic extension of the
 <loc href="#feature-length"><code>#length</code></loc> feature.</p>
 <p>It is an error for a content profile to require or permit use of the <code>#length-version-2</code> feature
 but prohibit use of any of the following features:
-<loc href="#feature-length"><code>#length</code></loc> or
+<loc href="#feature-length"><code>#length</code></loc>,
+<loc href="#feature-length-real-version-2"><code>#length-real-version-2</code></loc>, or
 <loc href="#feature-length-root-container-relative"><code>#length-root-container-relative</code></loc>.</p>
 </div3>
 <div3 id="feature-letterSpacing">
@@ -23637,6 +23654,12 @@ is optional (O), for a TTML <loc href="#terms-content-processor">content process
 <td css="text-align:center;">O</td>
 </tr>
 <tr>
+<td><loc href="#feature-length-real-version-2"><code>#length-real-version-2</code></loc></td>
+<td css="text-align:center;">2</td>
+<td css="text-align:center;">O</td>
+<td css="text-align:center;">O</td>
+</tr>
+<tr>
 <td><loc href="#feature-length-root-container-relative"><code>#length-root-container-relative</code></loc></td>
 <td css="text-align:center;">2</td>
 <td css="text-align:center;">O</td>
