diff --git a/CHANGELOG.md b/CHANGELOG.md
index 98e1811a..92fe9355 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@ about writing changes to this log.
 
 ## [Unreleased]
 
+- Bumped digital post max subject length to 50 characters
+
 ## [1.1.0] 2023-02-15
 
 - Added check for updated changelog.
diff --git a/src/Service/DigitalPostHelper.php b/src/Service/DigitalPostHelper.php
index 3e54ec9b..b23fe51c 100644
--- a/src/Service/DigitalPostHelper.php
+++ b/src/Service/DigitalPostHelper.php
@@ -20,11 +20,13 @@ class DigitalPostHelper extends DigitalPost
     /**
      * Maximum length of digital post subject.
      *
-     * It's not obvious, i.e. clearly documented, what the maximum length actually
-     * is, but XSDs embedded in the documentation on
-     * https://digitaliseringskataloget.dk/integration/sf1600 suggest that it's 34.
+     * https://docs.kombit.dk/integration/sf1600/2.5/pakke > "SF1600 - Print på
+     * Serviceplatformen v.2.5.pdf" > Page 76:
+     *
+     * > Titel på dokumentet. Ved forsendelser til eBoks, må der maksimalt
+     * > angives 50 tegn.
      */
-    public const SUBJECT_MAX_LENGTH = 34;
+    public const SUBJECT_MAX_LENGTH = 50;
 
     private array $serviceOptions;