diff --git a/FAQ.md b/FAQ.md
index 280f85f3dd..af5291748f 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -2992,7 +2992,7 @@ Note that a regular expression supports an *or* operator, so if you want to matc
 ```
 
 Note that [dot all mode](https://developer.android.com/reference/java/util/regex/Pattern#DOTALL) is enabled
-to be able to match [unfolded headers](https://tools.ietf.org/html/rfc2822#section-3.2.3).
+to be able to match [unfolded headers](https://datatracker.ietf.org/doc/html/rfc5322#section-3.2.23).
 
 <br />
 
diff --git a/index.html b/index.html
index bf32b0762e..1852f9ec4a 100644
--- a/index.html
+++ b/index.html
@@ -1633,7 +1633,7 @@ X-Google-Original-From: Somebody &lt;somebody+extra@example.org&gt;</code></pre>
 <pre><code>.*@.*\.xyz&gt;</code></pre>
 <p>Note that a regular expression supports an <em>or</em> operator, so if you want to match multiple senders, you can do this:</p>
 <pre><code>.*alice@example\.org.*|.*bob@example\.org.*|.*carol@example\.org.*</code></pre>
-<p>Note that <a href="https://developer.android.com/reference/java/util/regex/Pattern#DOTALL">dot all mode</a> is enabled to be able to match <a href="https://tools.ietf.org/html/rfc2822#section-3.2.3">unfolded headers</a>.</p>
+<p>Note that <a href="https://developer.android.com/reference/java/util/regex/Pattern#DOTALL">dot all mode</a> is enabled to be able to match <a href="https://datatracker.ietf.org/doc/html/rfc5322#section-3.2.23">unfolded headers</a>.</p>
 <p><br /></p>
 <p><a name="expression_conditions"></a> <strong>Expressions</strong></p>
 <p>Since version 1.2174 it is possible to use expression conditions like:</p>