https://spaceinvader.me/2017/02/19/...evelation-the-shenzhou-becomes-the-discovery/ I take this with a grain of a salt as it seems to be written from someone who just hates the look of Discovery itself.
The Shenzou and her captain are listed as being in all 13 episodes, but "assisting" the crew of the Discovery, so this is already nonsense.
The earlier rumor was more believe-able than this. The rumor that said that Discovery was a product of reversed Engineered by Section 31 that stolen by a bunch of Klingons.
The fan speculation and endless click bait type articles are getting so very tiresome. I will be very happy when they release actual information to shut these bloggers/vloggers up. The guys that claim to have sources inside the production really get old too. I can't imagine anyone working on the show would risk their career to leak ship/plot details to an Internet blogger.
Whoever they are, they need a copywriter who knows that "casted" is not the proper past tense for the verb "cast" (it is archaic), as seen used in the title of the article below found on that website: Star Trek Discovery: Klingons Casted The accepted past tense for "cast" is "cast". Sure, you can find "casted" being used today, but that's only due to ignorance.