Upgrading from MD 2011 to MD 2019 is a pretty large leap. But, I agree that there should still be no loss of data in doing so.
Something that you could try is to incrementally upgrade through the various versions.
The older versions are available in demo mode so that you can upgrade through each one.
Install > Upgrade > check the data > Uninstall > Install the next version > Upgrade > repeat.
You can d/l the older versions here: http://infinitekind.com/previous-versions-of-moneydance
Make sure to keep your original MD 2011 data file safe and secured. Use a copy to go through the incremental upgrades.