Hi there, @RSActg,
Thanks for your time getting in touch with us today. I can share some insights about upgrading your QuickBooks version.
Typically, if both the old and new versions are installed on the same computer, your data will automatically be updated to the most recent file. However, there are a few reasons why there are missing transactions or information that are not carried over. Here are some:
At the moment QuickBooks is unable to detect missing data after a QuickBooks upgrade. That is why during the upgrade process you are required to create a backup copy for your data's security.
Here's a great article you can check to know more about upgrading your company file: Upgrade to a New QuickBooks Desktop Version
That should get you on the right track, @RSActg. Please update me if you have any more questions about your file conversion. I'm here to help. Have a good one!