GX-Entwicklung

Steps to reproduce:

1. Create a guest order
2. Create a withdrawal for this order
3. Update the customer_id in the withdrawals database table from NULL to 0.
4. Open the withdrawals page in the Gambio Admin (Orders > Withdrawals)

Expected:
The withdrawals overview lists the withdrawal.

Actual:
An error message is displayed, that withdrawals cannot be loaded.

The v4.7.1.1 update updated the customer_id in the withdrawals table, if the customer does not exist anymore. Instead of setting the value to NULL it was set to 0.