Hi, cannot select the old GST code (in 8%) in the dropdown list during supplier invoice entry. I thot I should be able to select any GST code that is setup already.

I'm here to share some information about GST codes, angeline. 

In line with the new tax adjustments in Singapore, we have updated our GST rates to ensure compliance. Purchases of goods and services from GST-registered businesses made before January 1, 2024, will be subject to GST at 8%, and those made on or after January 1 of the current year will be subject to GST at 9%.    

However, we can still create additional custom tax rates. Here's how: 

1. Go to the Tax Centre, and select Add tax.
2. Choose which type of tax rate you want to set up.
3. Enter the details of your tax rate.
4. Once done, click Save.

For more info, visit this guide: How do I set up sales GST rates and use them on forms? (International QBO). 

Moreover, if rates don't apply to you, you can deactivate them. Also, you can review a GST/Tax report to show what you have previously filed for but have since changed, deleted, or even added. 

Hit the Reply button if you have any inquiries about managing tax rates in QuickBooks Online. I'll be here to assist. Take care!