Hi, ashevillerowing.

Allow me to share some information about updating customers via the third-party application.

Your time is valuable to us, as well as the ability for you to update customers through the third-party application. I can assure you that the engineering team is looking into this and hope to soon have more information regarding this update issues. I'll share your feedback with them to let them know about the changes you'd like to see made.

We aren't able to tell when a feature will be available. We share recent happenings and future developments on our blog. Through this, you're able to get the latest news about QuickBooks and what our Product Care Team is working on. 
You can check out this link: https://quickbooks.intuit.com/blog/.

For additional help, you can call our dedicated team who will be happy to assist you. Our contact details can be found here along with our opening hours.

I wish you and your business continued success. I'm here if you have any other questions.