How do i tell which version of qbo my client uses

Hello there, @uleytax, 

Let's go to your client's Billing & Subscription page so you can determine his/her QBO version. Please make sure you have an admin access to view this information. 

Here are the steps: 

1. Open your client's company. 
2. Go to the Gear icon at the upper right. 
3. Select Account and Settings. 
4. Go to Billing & Subscription from the left menu. 
5. Check the version your client is currently subscribed to. 

To help you effectively manage your company and client's billing details, here's a great article you can refer to: Account and Settings. 

I'll be around to help if you need further assistance. Have an awesome day.