When creating a new file type I assigned an icon but the icon only gets associated with the file type when the extension is in upper case. I am unable to create a lower case file type, unlike Opus version 11 which a friend of mine uses. This is a step backwards from version 11. My friend is not going to upgrade to a newer version which lacks a facility in the older version. Is this deficiency likely to be resolved in an update? I hope so as I always use lower case file extensions as they use less space.
Extension matching should never be case sensitive.
Can you tell us what you're doing exactly?
(And why are you asking for your friend? 
)
Edit: The extensions in the File Types list may be displayed as uppercase, but that shouldn't matter to anything. Actual files can have lowercase extensions and will still match the type you have created. Filenames in Windows are not case-sensitive.