1 files changed, 12 insertions, 7 deletions

diff --git a/draft-schanzen-r5n.xml b/draft-schanzen-r5n.xml
index 8cf874c..9ed5000 100644
--- a/draft-schanzen-r5n.xml
+++ b/draft-schanzen-r5n.xml
@@ -2490,20 +2490,25 @@ BEGIN
         also be impossible due to lack of storage capacity.
       </t>
       <t>
-        Applications can and should define their own block types.
         The block type determines the format and handling of the block
-        payload by peers in <tt>PutMessages</tt> and <tt>ResultMessages</tt>.
-        Block types <bcp14>MUST</bcp14> be registered with GANA
-        (see <xref target="gana_block_type"/>).
+        payload by peers in <tt>PutMessages</tt> and
+        <tt>ResultMessages</tt>.  Applications can and should define
+        their own block types.  Block types <bcp14>MUST</bcp14> be
+        registered with GANA (see <xref target="gana_block_type"/>).
+        Especially when new block types are introduced, some peers
+        <bcp14>MAY</bcp14> lack support for the respective block
+        operations.
       </t>
       <t>
       </t>
       <section anchor="block_functions">
         <name>Block Operations</name>
           <t>
-            Block validation may be necessary for all types of DHT
-            messages.  To enable these validations, any block type
-            specification <bcp14>MUST</bcp14> define the following functions:
+            Block validation operations are used as part of message
+            processing (see <xref target="p2p_messages"/>) for all
+            types of DHT messages.  To enable these validation
+            operations, any block type specification
+            <bcp14>MUST</bcp14> define the following functions:
           </t>
           <dl>
             <dt>ValidateBlockQuery(Key, XQuery)