diff --git a/cgi-bin/addnotes.pl b/cgi-bin/addnotes.pl
index bdc4b04..6ea4e5d 100755
--- a/cgi-bin/addnotes.pl
+++ b/cgi-bin/addnotes.pl
@@ -96,6 +96,8 @@
                    end
     where name = $1
           and status = 'approved'
+	      -- makes request idempotent
+          and sys_notes is distinct from nullif($2,'')
 
 };
 
diff --git a/cgi-bin/upgrade.pl b/cgi-bin/upgrade.pl
index 7f80207..540b415 100755
--- a/cgi-bin/upgrade.pl
+++ b/cgi-bin/upgrade.pl
@@ -132,24 +132,28 @@
 	$os_version       ||= $old_os;
 	$compiler_version ||= $old_comp;
 
-	my $new_personality = q{
+	# makes request idempotent
+	if ($os_version ne $old_os || $compiler_version ne $old_comp)
+	{
+		my $new_personality = q{
 
-    insert into personality (name, os_version, compiler_version)
-	values (?,?,?)
+		insert into personality (name, os_version, compiler_version)
+		values (?,?,?)
 
-    };
+		};
 
-	$sth = $db->prepare($new_personality);
-	$rv = $sth->execute($animal, $os_version, $compiler_version);
+		$sth = $db->prepare($new_personality);
+		$rv = $sth->execute($animal, $os_version, $compiler_version);
 
-	$sth->finish;
+		$sth->finish;
 
-	unless ($rv)
-	{
-		print "Status: 470 new data insert\nContent-Type: text/plain\n\n";
-		print "error: $db->errstr\n";
-		$db->disconnect;
-		exit;
+		unless ($rv)
+		{
+			print "Status: 470 new data insert\nContent-Type: text/plain\n\n";
+			print "error: $db->errstr\n";
+			$db->disconnect;
+			exit;
+		}
 	}
 }