Yes you can open a 2015 file in 2019 by just starting the 2019 version and browsing for your file and selecting it to open BUT after updating it can no longer be opened by 2015 program. That is why I always suggest using backup/restore when upgrading so that you always have the older existing version to fall back on if something goes wrong. In fact you shoukd always consider installing the upgraded 2019 as Advanced and choose to keep older version rather than Express which deletes older version of software in the process, leaving you with no alternative if something doesn't work as it should
I'm trying to restore a back up copy from 2015 to my 2017 (also tried on 2019) keeps telling me that I need to have the administrator update the file, won't let me restore. It's a client file, they have no clue and I don't know what to tell him
Hello there, @Advtaxserv.
I want to help ensure isolate this error so you keep your QuickBooks up and running.
You'll need to log into QuickBooks Desktop as the admin user. Once completed, you can now start updating your client's company file.
For additional insights, you may check out this article: Upgrade to a new QuickBooks Desktop version.
Feel free to click the Reply button if you have other questions about restoring your company file. I'm always here to help.