TLDR; you can convert Series 5 Word documents to Text, HTML5 or Markdown using this online service. No guarantees are made, and for transparency you can view the code here.
In 2021, I wrote about my workflow for getting draft documents out of my Psion and in to my blog. It worked, but it required multiple steps and was a bit of a kludge.
Psiconv is a conversion utility originally by Frodo Looijaard designed to convert Psion Word files to HTML or plain text.
It’s written in C, and while it’s plain text mode is fine, is limited to outputting HTML4. Pandoc is a universal
document converter, but doesn’t particularly like the HTML4 produced by psiconv. I extended Psiconv to output
HTML5 to act as an input for Pandoc.
Having working psiconv + pandoc opens up some powerful possibilities. I built a small web app to wrap some common options (HTML5, Text, Markdown) and built a docker file to manage building psiconv and the application. The final application is hosted on Azure and freely available for you to convert your own files.
As a disclaimer, the application does use temporary files on the container, but cleans up after processing. If you’re concerned, please see the source of the web app for details.
I’d appreciate a comment if this application is useful to you.