Does opening an older file in Accountant Desktop 2021 charge the client?

Thanks for checking in with us, GG69.

Ideally, the client and accountant using the Accountant's Copy feature should use the same version or year of QuickBooks Desktop. Though you can still work on the Accountant's Copy using a different version as long as the gap between the versions is just one year, and the accountant has a more recent version. For more details about this one, see the Use the Accountant's Copy article. 

On the other hand, your client will be only charged if they will upgrade their QuickBooks to the latest version. To learn more about company file compatibility to avoid issues and errors when upgrading the software, see the Company file compatibility with QuickBooks Desktop when upgrading article for more details. 

If you can't still open your client's file, I'd suggest contacting our Technical Support Team. They'll pull up your account in a secure environment and help you with this one. You may send a message via chat, call us at a time convenient to you, or we’ll get in touch with you instead. To ensure we address your concern, our representatives are available from 6:00 AM to 6:00 PM on weekdays and 6:00 AM - 3:00 PM on Saturdays, PST. See our support hours and types for more details about this one. Here's how to reach them: 

1. Click the Help icon on the top menu. 
2. Choose QuickBooks Desktop Help. 
3. Tap Contact us.
4. Select Search for something else and enter your concern in the Tell us more about your question: field. 
5. Tap Search. 
6. Choose Start a Message or Get Phone Number to connect with our support. 

Feel free to visit our Account management page for more insights about managing your Intuit Account.

I'd like to know how things going after contacting our support agent, as I want to ensure this is resolved for you. Feel free to reply to this post and I'll get back to you. Take care always.