A search of the forum using the search option (magnifying glass icon) yields answers to all your questions.
https://community.wd.com/t/firmware-worth-updating/149369
https://community.wd.com/t/app-transmission-v2-84-for-firmware-v4-12-2014/93424
https://community.wd.com/t/app-qbittorrent-various-versions-for-firmware-v4-01-2016/146729
https://community.wd.com/t/faq-twonky-dlna-media-server-setup-use/95373
https://community.wd.com/t/guide-debrick-a-completely-dead-mycloud/92253
https://community.wd.com/t/guide-how-to-unbrick-your-2tb-3tb-4tb-my-cloud/93336
