diff --git a/README.md b/README.md
index 5d122dc..cde60f6 100644
--- a/README.md
+++ b/README.md
@@ -99,14 +99,14 @@ Just reading the "Safety" section below will already give you an idea.
 - You can add/rename/delete tables and columns (also change types/definitions) whenever you want,
 since each time you press "Generate Files", change details between the current and last version are generated
 (if there were any) and via an additional table with
-table metadata jSQL-Gen keeps track of the actual tables state/version. Keep in mind that manual changes
+table metadata, jSQL-Gen keeps track of the actual tables' state/version. Keep in mind that manual changes
 to the database directly could result in issues.
 
 ### 🗄 SQL & JDBC
-- The generated SQL code should be compatible with all types of SQL databases.
+- The generated SQL code should be compatible with all types of SQL databases. However no promises are made except for MariaDB/MySQL. Open an issue if there are problems with your database software.
 - The generated Java (and JDBC) code does not require any third party libraries and should work with Java 8 or higher.
 - Supports all JDBC data types + some extras like enum. ![img.png](img.png)
-- `NULL` is not allowed, instead use the `DEFAULT ''` keyword.
+- `NULL` is not allowed, instead use the `DEFAULT ''` keyword or `-1` for null id references.
 - Supports DEFAULT for blobs. Example: `file BLOB DEFAULT ''`.
 - Supports SQL DEFAULT for `NOW(), CURDATE(), CURTIME()`.