[MKVToolNix] How to enable "use legacy MIME types for font attachments"?

[Compositor]

The new MIME types for font attachments is breaking the ability of subtitle files to read embedded subs in an mkv. I need to get MKVToolNix to switch back to the legacy types. I read the changelog that the option is there, but I can't find it in the Output>Options window where the less used options are usually found or anywhere else. Please help me find it.

I would be most grateful for any assistance.

Update: Finally found it in the UI Preferences window.