diff --git a/README.md b/README.md
index 4373d37..2f52771 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,10 @@ You can download the latest SQLite release of the [China Biographical Database](
 
 * https://huggingface.co/datasets/cbdb/cbdb-sqlite/blob/main/latest.zip
 
-----
+## Data Limitations
+
+* The ZZZ releases are now deprecated in favor of views. Use [`create_views.sh`](./scripts/create_views.sh) to create views in the SQLite file.
+* The SQLite releases after 2025-05 may not include up-to-date **Index Year** (`BIOG_MAIN.c_index_year`), **Index Year Type Code** (`BIOG_MAIN.c_index_year_type_code`) and **Index Year Source ID** (`BIOG_MAIN.c_index_year_source_id`) information.
 
 ## Historical releases