diff --git a/protocol.html b/protocol.html
index 26ecef78..22544b7d 100644
--- a/protocol.html
+++ b/protocol.html
@@ -1054,12 +1054,22 @@ <h3 property="schema:name">Security and Privacy Review</h3>
           <section class="appendix" id="sparql-update-subset" inlist="" rel="schema:hasPart" resource="#sparql-update-subset">
             <h2 property="schema:name">Appendix - A subset of SPARQL Update for Solid</h2>
             <div datatype="rdf:HTML" property="schema:description">
+              <section id="sparql-subset-overview" inlist="" rel="schema:hasPart" resource="#sparql-subset-overview">
+                <h3 property="schema:name">Overview</h3>
+		 <div datatype="rdf:HTML" property="schema:description">
+                   <p><em>This section is non-normative.</em></p>
+
+		   <p>The objective of the subset is to identify a subset of SPARQL 1.1 Update [<cite><a class="bibref" href="#bib-sparql-overview">SPARQL</a></cite>] that is relatively easy to implement and contains features that are most commonly used. It thus takes variations of the <code>INSERT</code> and <code>DELETE</code> operations and allows operations on basic triple patterns only. The subset is compatible with SPARQL 1.1 Update and is defined in terms of a <a href="#sparql-subset-grammar">grammar</a>. To further examine the definition, see <a href="https://services.w3.org/yacker/uploads/SPARQL_patch_solid?lang=perl&markup=html">the Yacker validator</a>.
+		   </p>
+		 </div>
+	      </section>
+
               <section id="sparql-subset-grammar" inlist="" rel="schema:hasPart" resource="#sparql-subset-grammar">
                 <h3 property="schema:name">Grammar</h3>
 		<div class="note" id="sparql-subset-definition-note" inlist="" rel="schema:hasPart" resource="#sparql-subset-definition-note">
                     <h4 property="schema:name"><span>Note</span>: Definition of SPARQL Update Subset</h4>
                     <div datatype="rdf:HTML" property="schema:description">
-                      <p>This specification alters the grammar of 10 rules in the original grammar of the SPARQL 1.1 Query Language [<cite><a class="bibref" href="#bib-sparql-overview">SPARQL</a></cite>] grammar and introduces another 10 new rules to accommodate for <code>INSERT DATA</code> and <code>DELETE DATA</code>, which was defined in the language definition but not precisely defined in the grammar. This specification references the original grammar definition where no changes were made.
+                      <p>This specification alters the grammar of 8 rules in the original grammar of the SPARQL 1.1 Query Language [<cite><a class="bibref" href="#bib-sparql-overview">SPARQL</a></cite>] grammar and introduces another 10 new rules to accommodate for <code>INSERT DATA</code> and <code>DELETE DATA</code>, which was defined in the language definition but not precisely defined in the grammar. This specification references the original grammar definition where no changes were made.
 		    </div>
 		</div>
 
@@ -1070,7 +1080,7 @@ <h4 property="schema:name"><span>Note</span>: Definition of SPARQL Update Subset
 			<td><code>[30p]  </code></td>
 			<td><code><a id="rUpdate1" name="rUpdate1">Update1</a></code></td>
 			<td>  ::=  </td>
-			<td><code><a href="https://www.w3.org/TR/sparql11-query/#rPrologue">Prologue</a> ( <a href="#rInsertData">InsertData</a> | <a href="#rDeleteData">DeleteData</a> |  <a href="#rModify">Modify</a> ) </code></td> 
+			<td><code><a href="https://www.w3.org/TR/sparql11-query/#rPrologue">Prologue</a> ( <a href="#rInsertData">InsertData</a> | <a href="#rDeleteData">DeleteData</a> | <a href="https://www.w3.org/TR/sparql11-query/#rDeleteWhere">DeleteWhere</a> | <a href="#rModify">Modify</a> ) </code></td> 
 		      </tr>
 		      <tr valign="baseline">
 			<td><code>[38p]  </code></td>
@@ -1084,11 +1094,17 @@ <h4 property="schema:name"><span>Note</span>: Definition of SPARQL Update Subset
 			<td>  ::=  </td>
 			<td><code><span class="token">'DELETE DATA'</span> <span class="token">'{'</span> <a href="#rTripleData">TripleData</a> <span class="token">'}'</span> </code></td>
 		      </tr>
+		      <tr valign="baseline">
+			<td><code>[40p]  </code></td>
+			<td><code><a id="rDeleteWhere" name="rDeleteWhere">DeleteWhere</a></code></td>
+			<td>  ::=  </td>
+			<td><code><span class="token">'DELETE WHERE'</span> <span class="token">'{'</span>  <a href="https://www.w3.org/TR/sparql11-query/#rTriplesTemplate">TriplesTemplate</a> <span class="token">'}'</span> </code></td>
+      </tr>
 		      <tr valign="baseline">
 			<td><code>[41p]  </code></td>
 			<td><code><a id="rModify" name="rModify">Modify</a></code></td>
 			<td>  ::=  </td>
-			<td><code>( <a href="#rDeleteClause">DeleteClause</a> <a href="#rInsertClause">InsertClause</a>? | <a href="#rInsertClause">InsertClause</a> )  <span class="token">'WHERE'</span> <a href="#rGroupGraphPattern">GroupGraphPattern</a></code></td>
+			<td><code>( <a href="#rDeleteClause">DeleteClause</a> <a href="#rInsertClause">InsertClause</a>? | <a href="#rInsertClause">InsertClause</a> )  <span class="token">'WHERE'</span> <span class="token">'{'</span>  <a href="https://www.w3.org/TR/sparql11-query/#rTriplesTemplate">TriplesTemplate</a> <span class="token">'}'</span> </code></td>
 		      </tr>
 		      <tr valign="baseline">
 			<td><code>[42p]  </code></td>
@@ -1108,24 +1124,6 @@ <h4 property="schema:name"><span>Note</span>: Definition of SPARQL Update Subset
 			<td>  ::=  </td>
 			<td><code><a href="#rTriplesDataSameSubject">TriplesDataSameSubject</a> ( <span class="token">'.'</span> <a href="#rTripleData">TripleData</a>? )?</code></td>
 		      </tr>
-		      <tr valign="baseline">
-			<td><code>[53p]  </code></td>
-			<td><code><a id="rGroupGraphPattern" name="rGroupGraphPattern">GroupGraphPattern</a></code></td>
-			<td>  ::=  </td>
-			<td><code><span class="token">'{'</span> <a href="#rGroupGraphPatternSub">GroupGraphPatternSub</a> ) <span class="token">'}'</span></code></td>
-		      </tr>
-		      <tr valign="baseline">
-			<td><code>[54p]  </code></td>
-			<td><code><a id="rGroupGraphPatternSub" name="rGroupGraphPatternSub">GroupGraphPatternSub</a></code></td>
-			<td>  ::=  </td>
-			<td><code><a href="#rTriplesBlock">TriplesBlock</a></code></td>
-		      </tr>
-		      <tr valign="baseline">
-			<td><code>[55p]  </code></td>
-			<td><code><a id="rTriplesBlock" name="rTriplesBlock">TriplesBlock</a></code></td>
-			<td>  ::=  </td>
-			<td><code><a href="https://www.w3.org/TR/sparql11-query/#rTriplesSameSubject">TriplesSameSubject</a> ( <span class="token">'.'</span> <a href="#rTriplesBlock">TriplesBlock</a>? )?</code></td>
-		      </tr>
 		      <tr valign="baseline">
 			<td><code>[75d]  </code></td>
 			<td><code><a id="rTriplesDataSameSubject" name="rTriplesDataSameSubject">TriplesDataSameSubject</a></code></td>