diff --git a/SeedDMS_Core/Core/inc.ClassAttribute.php b/SeedDMS_Core/Core/inc.ClassAttribute.php
index a51d6c81f..fff7423a3 100644
--- a/SeedDMS_Core/Core/inc.ClassAttribute.php
+++ b/SeedDMS_Core/Core/inc.ClassAttribute.php
@@ -259,6 +259,14 @@ class SeedDMS_Core_Attribute { /* {{{ */
 
 		$this->_value = $value;
 
+		/* Check if 'onPostUpdateAttribute' callback is set */
+		if(isset($this->_dms->callbacks['onPostUpdateAttribute'])) {
+			foreach($this->_dms->callbacks['onPostUpdateAttribute'] as $callback) {
+				if(!call_user_func($callback[0], $callback[1], $this->_obj, $this->_attrdef, $value)) {
+				}
+			}
+		}
+
 		return true;
 	} /* }}} */
 
diff --git a/SeedDMS_Core/Core/inc.ClassObject.php b/SeedDMS_Core/Core/inc.ClassObject.php
index bc02592fa..0f7b90eb8 100644
--- a/SeedDMS_Core/Core/inc.ClassObject.php
+++ b/SeedDMS_Core/Core/inc.ClassObject.php
@@ -269,6 +269,15 @@ class SeedDMS_Core_Object { /* {{{ */
 			$attr = new SeedDMS_Core_Attribute($db->getInsertID($tablename), $this, $attrdef, $value);
 			$attr->setDMS($this->_dms);
 			$this->_attributes[$attrdef->getId()] = $attr;
+
+			/* Check if 'onPostAddAttribute' callback is set */
+			if(isset($this->_dms->callbacks['onPostAddAttribute'])) {
+				foreach($this->_dms->callbacks['onPostAddAttribute'] as $callback) {
+					if(!call_user_func($callback[0], $callback[1], $this, $attrdef, $value)) {
+					}
+				}
+			}
+
 			return true;
 		}
 
diff --git a/SeedDMS_Core/package.xml b/SeedDMS_Core/package.xml
index 16fc74a1c..c6a2273ee 100644
--- a/SeedDMS_Core/package.xml
+++ b/SeedDMS_Core/package.xml
@@ -28,6 +28,7 @@
 - getLastWorkflowLog() returns a workflow entry even if the workflow has ended
 - backport setFileType() from 6.0.x
 - add SeedDMS_Core_File::fileExtension()
+- add callbacks on onPostUpdateAttribute and onPostAddAttribute
  </notes>
  <contents>
   <dir baseinstalldir="SeedDMS" name="/">