diff --git a/libraries/liblmdb/lmdb.h b/libraries/liblmdb/lmdb.h
index dc64b12..d7e6fb0 100644
--- a/libraries/liblmdb/lmdb.h
+++ b/libraries/liblmdb/lmdb.h
@@ -1335,7 +1335,8 @@ int mdb_cursor_get(MDB_cursor *cursor, MDB_val *key, MDB_val *data,
*
#MDB_CURRENT - overwrite the data of the key/data pair to which
* the cursor refers with the specified data item. The \b key
* parameter is not used for positioning the cursor, but should
- * still be provided.
+ * still be provided. If using sorted duplicates (#MDB_DUPSORT)
+ * the data item must still sort into the same place.
* #MDB_NODUPDATA - enter the new key/data pair only if it does not
* already appear in the database. This flag may only be specified
* if the database was opened with #MDB_DUPSORT. The function will