We recently updated Moodle to 3.10.1 (Build 20210211). A day later, it was noticed that in grading view, instead of the submitted document being converted and displayed, an error message "Alert Cannot open the PDF. The file may be corrupt, or in an unsupported format".
I checked the environment in site administration and found that at the bottom "The version of unoconv you have installed is not supported."
I hadn't made any changes to it, so checked the versions and paths:
/usr/bin/unoconv (Version 0.9.0)
/usr/bin/python (Version python 3.7.7, LibreOffice 126.96.36.199)
All of which appears just fine.
That leaves me stuck on how to resolve the reported error - has anyone experienced this or have any guidance to resolve it please?