we used fileuploadbuttonasynchronous and defined "jpg" (in small letters) as allowed file extension.
Some users reported us now that they were not able to upload image files. After a short analysis we found out that their image files had the extension "JPG" (in big letters). As consequence the upload of this "JPG" file was not possible with fileuploadbuttonasynchronous.
Do you think you can make the check for the correct file extension case insensitive?