So for now maximum size of filenames/directories are 107 characters (as it limitation of FFS). To set that maximum we use Settings->Evnvironment->Directories->Maximum Filename Length.
While, we be pretty good to have ability to setup it up to 255 (at least) characters lenght, so on partitions which can handle more than 107 characters in filenames/directories length it will works.
As we discuss before , that will be not very easy:
While it was possible to add large disk and large file support without changing a lot of structures, >107 character file name support is an entirely different beast. This limitation comes from the heavy internal usage of struct FileInfoBlocks. It's not only used when the files are examined, but DOpus5 embeds it in a lot of its own structures. Removing this limitation would require a major rewrite, with a lot of changes.