Plex for My Cloud Home totally outdated and useless

I have a WD My Cloud Home and the Plex Media Server version is, totally outdated and I can’t watch any tv show o movie I have, I tried to set up another Plex Media Server in my PC with the last version and all gone well, anyone know if they are thinking to update it? it 's really annoying to have a NAS and can’t watch anything because the movie stops every 5 seconds. All of this is when I cast it to the Chromecast ultra or when I saw them in my mobile, my internet connection is 600 mb, it’s not for the speed of internet

For Plex have you looked at this. I found it with a Google search.

Are you saying you get 600 Mbps? See example test image below.

There are media server updates for the My Cloud hard drives, for the My Cloud Home there aren’t, it depends that WD update them and the last update was in march 2018
Yes, my internet connection is not the problem