Upload file for CSS theme
You may want to upload an OTF file extension (or similar file) using the Upload file option to the Site Manager -> Development -> CSS stylesheets -> your stylesheet -> Theme section, only to find out you cannot upload this type of file. This article describes the simple fix needed to achieve this result.
You will need to edit the ~\CMSModules\AdminControls\Controls\CSS\ThemeEditor.ascx.cs file on line 57 where you see the following code:
config.AllowedExtensions = "gif;png;bmp;jpg;jpeg;css;skin";
you can add your desired file extension to this list. Using the
.otf extension as an example:
config.AllowedExtensions = "gif;png;bmp;jpg;jpeg;css;skin;otf";
after adding this extension, you can now upload OTF files to this location.