Hi timtam
Some of your comments are inconsistent, so it would help if you can clarify. Specifically you wrote:
"When opening the file in MYOB 2023 and trying to upload it the MYOB screen says that the version used is 2019.3."
When you update a file, the current version being used creates a backup with the old version number in brackets. Say you file is called test1.myox. If this is a v2019.2 company files, when you try to open this in AR2023.5, MYOB will create a backup called test1 (2019.2).myox. Your updated file will be called test1.myox.
You cannot open test1.myox in AR2019.2.
You cannot open test1 (2019.2).myox in AR2023.5. It must be updated to AR2023.5 first.
So when you ran AR2023.5 and opened the company file, did you receive any messages? If there is a version problem you will see that well before you try to upload it online.
Suggest your try again. Ensure you are running AR2023.5 - make a note to check it is AR2023.5 on the welcome screen. Then select the company file that has already been updated to AR2023.5. Then try to upload. If you get the same message, take a screenshot. Then open Help About and take a screenshot of the version number. Attach both screenshots to your reply.
Regards
Gavin