Update concept-custom-classifier.md

Author: laujan

articles/applied-ai-services/form-recognizer/concept-custom-classifier.md

@@ -18,6 +18,11 @@ recommendations: false
 
 **This article applies to:** ![Form Recognizer v3.0 checkmark](media/yes-icon.png) **Form Recognizer v3.0**.
 
+> [!IMPORTANT]
+>
+> * Custom classification model is currently in public preview. Features, approaches, and processes may change, prior to General Availability (GA), based on user feedback.
+>
+
 Custom classification models are deep-learning-model types that combine layout and language features to accurately detect and identify documents you process within your application. Custom classification models can classify each page in an input file to identify the document(s) within and can also identify multiple documents or multiple instances of a single document within an input file.
 
 ## Model capabilities