PRE-REQUISITES This MUST be tested on Windows and Linux . To start the test, you MUST install unoconv version 0.6. Linux TIP : To start the test, I've recommend you to install unoconv through apt-get sudo apt-get install unoconv , this will install the unoconv version{{0.6}} the current version on the ubuntu repo. Then, once you test the warning message of not supported version, download the deb package and install it using the command dpkg. On windows, I recommend you to start our Win10-AllDrivers VM and follow the instructions on the Unoconv install docs , basically you will need to clone the unoconv github and switch between tags. TEST Visit Site administration ► Server ► Environment You should see the following warning message under Other checks : The version of unoconv you have installed is not supported. Moodle's assignment grading feature requires version 0.7 or higher. Visit Site administration ► Plugins ► Activity modules ► Assignment ► Feedback plugins ► Annotate PDF Click on Test unoconv path link under Path to unoconv document converter You should see an warning saying the unoconv version is not supported. Now, install the unoconv version 0.7 or higher Confirm the version by executing: unconv --version Site administration ► Server ► Environment You should NOT see any unoconv related warning. Visit Site administration ► Plugins ► Activity modules ► Assignment ► Feedback plugins ► Annotate PDF Click on Test unoconv path link under Path to unoconv document converter On the unoconv test page, you should see confirmation the unoconv path appears to be properly configured... Click on the Download button and make sure a test pdf was generated. Docs page about unoconv: https://docs.moodle.org/31/en/Installing_unoconv