Release note for custom StreamField validation support (#7250)

CHANGELOG.txt

@@ -4,6 +4,7 @@ Changelog
 5.0 (xx.xx.xxxx) - IN DEVELOPMENT
 ~~~~~~~~~~~~~~~~
 
+ * Custom validation support for StreamField (Matt Westcott)
  * Add `WAGTAILIMAGES_EXTENSIONS` setting to restrict image uploads to specific file types (Aman Pandey, Ananjan-R)
  * Update user list column level to `Access level` to be easier to understand (Vallabh Tiwari)
  * Migrate `.button-longrunning` behaviour to a Stimulus controller with support for custom label element & duration (Loveth Omokaro)

docs/releases/5.0.md

@@ -11,7 +11,9 @@ depth: 1
 
 ## What's new
 
-### ...
+### Custom validation support for StreamField
+
+Support for adding custom validation logic to StreamField blocks has been formalised and simplified. For most purposes, raising a `ValidationError` from the block's `clean` method is now sufficient; more complex behaviours (such as attaching errors to a specific child block) are possible through block-specific subclasses of `ValidationError`. For more details, see [](streamfield_validation). This feature was developed by Matt Westcott.
 
 ### Other features