diff --git a/lam/HISTORY b/lam/HISTORY
index acff870c7..0436682d9 100644
--- a/lam/HISTORY
+++ b/lam/HISTORY
@@ -1,5 +1,7 @@
 September 2023
   - Accessibility improvements
+  - LAM Pro:
+   -> Custom fields: support "\" in date regex for text fields
 
 
 06.06.2023 8.4
diff --git a/lam/lib/html.inc b/lam/lib/html.inc
index da62877fd..74bacd1d9 100644
--- a/lam/lib/html.inc
+++ b/lam/lib/html.inc
@@ -810,6 +810,7 @@ class htmlInputField extends htmlElement {
 		$format = str_replace('yy', 'Y', $format);
 		$format = str_replace('dd', 'd', $format);
 		$format = str_replace('mm', 'm', $format);
+		$format = str_replace('\\', '\\\\', $format);
 		$this->calendarFormat = $format;
 	}