Thoth and MT-Newswatcher allow users to post and organize folders and files.
Osiris supports y-Encode if you are using Thoth 1.5 or greater. However, you may still use the original version and manually set your preferences using the script editor. Also, it is worth noting that Osiris is open source, built upon a core routine by Dennis R. Cohen.
It is important to ensure that you are using the current version of Thoth to avoid crashes when using Osiris. The software does require either Thoth or MT-Newswatcher for OS X to operate, but if you have those requirements covered, you may enjoy the streamlined experience Osiris provides for posting files in newsgroups.
Version 3.2: N/A