AdminStudio can convert suitable application installations in MSI and EXE format into MSIX, but MSIX is different enough from App-V that an App-V to MSIX conversion is not something that is supported. If this application can be converted to App-V, however, than it is likely convertible to MSIX as well.
As you likely know, Word 2003 is no longer officially supported by Microsoft. As this US-Cert alert states, there are no longer any security patches or other updates available for this software: https://us-cert.cisa.gov/ncas/alerts/TA14-069A-0 Be careful when it comes using unsupported and potentially vulnerable applications within your environment.
Flexera has partnerships with several service provides and other organizations around the world that can help you with packaging complex applications and scenarios. You can search for partners that help with this field of Application Readiness here.
Feel free to private message me your contact information if you'd like to be connected to some partners that can help.
Expert Flexeran on AdminStudio, Workflow Manager, and Software Vulnerability Manager / Research
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