This is a Factory Talk View Studio ME - Cautionary Tale I share in hopes it saves someone some headache.

I had a Panelview Plus 7 Professional 1500 HMI firmware version 10 running an application built for firmware 10 with Studio ME Version 12.

We contracted a System Integrator to use Studio 12 and build a modified *.mer for the Panelview with additional functions.

Installed the MER and all ran fine.

Recently I was asked to add another Analog Display to the HMI so I uploaded the MER and retored it to my Studio 12 development station.

But it errored when I tried to edit it for - 

The database ....file name.mdf cannot be opened because it is version 904.

Technote - https://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/968826/loc/en_US#__highlight speaks of an issue from 2020 where a non-standard sql was present when studio was installed.

A little digging and it turns out FTView Studio ME 12 use SQL 2012 and FTView Studio ME 13 use SQL 2019.  So even though Studio 13 built a firmware 10 mer that runs when you goto restore the Firmware 10 mer you need SQL 2019 if it was built with Version 13.

So much for passing projects backward between studio revisions by building a backward mer.