diff --git a/README.md b/README.md
index 6cd8e35..9902ef3 100644
--- a/README.md
+++ b/README.md
@@ -647,11 +647,11 @@ from dateutil.tz import UTC, tzlocal, gettz, datetime_exists, resolve_imaginary
 
 ### Format
 ```python
->>> dt = datetime.strptime('2015-05-14 23:39:00.00 +2000', '%Y-%m-%d %H:%M:%S.%f %z')
+>>> dt = datetime.strptime('2015-05-14 23:39:00.00 +0200', '%Y-%m-%d %H:%M:%S.%f %z')
 >>> dt.strftime("%A, %dth of %B '%y, %I:%M%p %Z")
 "Thursday, 14th of May '15, 11:39PM UTC+02:00"
 ```
-* **`'%Z'` only accepts `'UTC/GMT'` and local timezone's code. `'%z'` also accepts `'±HH:MM'`.**
+* **Format code `'%z'` accepts `'±HH[:]MM'` and returns `'±HHMM'` (or `''` if datetime is naive).**
 * **For abbreviated weekday and month use `'%a'` and `'%b'`.**
 
 ### Arithmetics
diff --git a/index.html b/index.html
index 8f4793a..dad4cd6 100644
--- a/index.html
+++ b/index.html
@@ -54,7 +54,7 @@
 
 <body>
   <header>
-    <aside>April 8, 2023</aside>
+    <aside>April 9, 2023</aside>
     <a href="https://gto76.github.io" rel="author">Jure Šorn</a>
   </header>
 
@@ -573,13 +573,13 @@ Point(x=<span class="hljs-number">1</span>, y=<span class="hljs-number">2</span>
 &lt;float&gt;  = &lt;DTa&gt;.timestamp()                <span class="hljs-comment"># Seconds since the Epoch, from aware datetime.</span>
 </code></pre></div>
 
-<div><h3 id="format-1">Format</h3><pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>dt = datetime.strptime(<span class="hljs-string">'2015-05-14 23:39:00.00 +2000'</span>, <span class="hljs-string">'%Y-%m-%d %H:%M:%S.%f %z'</span>)
+<div><h3 id="format-1">Format</h3><pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>dt = datetime.strptime(<span class="hljs-string">'2015-05-14 23:39:00.00 +0200'</span>, <span class="hljs-string">'%Y-%m-%d %H:%M:%S.%f %z'</span>)
 <span class="hljs-meta">&gt;&gt;&gt; </span>dt.strftime(<span class="hljs-string">"%A, %dth of %B '%y, %I:%M%p %Z"</span>)
 <span class="hljs-string">"Thursday, 14th of May '15, 11:39PM UTC+02:00"</span>
 </code></pre></div>
 
 <ul>
-<li><strong><code class="python hljs"><span class="hljs-string">'%Z'</span></code> only accepts <code class="python hljs"><span class="hljs-string">'UTC/GMT'</span></code> and local timezone's code. <code class="python hljs"><span class="hljs-string">'%z'</span></code> also accepts <code class="python hljs"><span class="hljs-string">'±HH:MM'</span></code>.</strong></li>
+<li><strong>Format code <code class="python hljs"><span class="hljs-string">'%z'</span></code> accepts <code class="python hljs"><span class="hljs-string">'±HH[:]MM'</span></code> and returns <code class="python hljs"><span class="hljs-string">'±HHMM'</span></code> (or <code class="python hljs"><span class="hljs-string">''</span></code> if datetime is naive).</strong></li>
 <li><strong>For abbreviated weekday and month use <code class="python hljs"><span class="hljs-string">'%a'</span></code> and <code class="python hljs"><span class="hljs-string">'%b'</span></code>.</strong></li>
 </ul>
 <div><h3 id="arithmetics">Arithmetics</h3><pre><code class="python language-python apache hljs">&lt;D/DT&gt;   = &lt;D/DT&gt;  ± &lt;TD&gt;                   <span class="hljs-comment"># Returned datetime can fall into missing hour.</span>
@@ -2934,7 +2934,7 @@ $ pyinstaller script.py --add-data '&lt;path&gt;:.'  <span class="hljs-comment">
  
 
   <footer>
-    <aside>April 8, 2023</aside>
+    <aside>April 9, 2023</aside>
     <a href="https://gto76.github.io" rel="author">Jure Šorn</a>
   </footer>
 
