diff --git a/options.xhtml b/options.xhtml
index 164f7857b..5fad00ea7 100644
--- a/options.xhtml
+++ b/options.xhtml
@@ -15569,7 +15569,7 @@ null or string</p>
 <p>Number of history lines to keep on file.</p>
 
 <p><span class="emphasis"><em>Type:</em></span>
-signed integer</p>
+null or signed integer</p>
 
 <p><span class="emphasis"><em>Default:</em></span>
 <code class="literal">100000</code></p>
@@ -15624,7 +15624,7 @@ list of string</p>
 <p>Number of history lines to keep in memory.</p>
 
 <p><span class="emphasis"><em>Type:</em></span>
-signed integer</p>
+null or signed integer</p>
 
 <p><span class="emphasis"><em>Default:</em></span>
 <code class="literal">10000</code></p>