Hi there, figuringitout1. Let me provide additional information about adding the attachments to your new company file.

Your Inbox folder is located on your old company file. First, find your company file using this file name: C:\Users\Public\Public Documents\Intuit\QuickBooks\Company Files.

Once you've located your company file, copy the attached folder from your old file and paste it into the location of your new company file.

I'll be adding this article again for your reference about attachments: QuickBooks Document Center: FAQs and common issues

In addition, you can refer to this article to check what features QBDT 2024 has: What’s new in QuickBooks Desktop 2024

Reply or post in the Community if you need anything else about managing your attachments in QBDT. I'm always here to help.