CCP has outlined the new Engineering Complexes (formally known as Industrial Arrays) coming in the November expansion (called Ascension).
https://community.eveonline.com/news/dev-blogs/building-dreams-introducing-engineering-complexes/
There are plenty of pictures to check out.
The Medium is called Raitaru, Large – Azbel, and XL – Sotiyo.
They use the same anchoring process as Citadels and work in much the same way aside different bonuses. That again means I won’t use them for any sort of serious solo game play as they are not suitable for it.
They will cost less – 40% lower than Medium Citadels (~0.7B), 60% less than Large Citadels (~5.2B), and 90% less than XL Citadels (~30B), have 33% less Hit Points, and require longer vulnerability periods (9 hours for Medium, 18 Large and 36 XL).
They are a little more restrictive in what ships can dock – the Large won’t dock Capital ships (aside Freighters, Orca, Bowhead), and the XL won’t dock Supercarriers.
You gain benefits from using them out of High-Sec, from a couple percentage points for manufacturing material input to up to almost twenty percentage points for manufacturing or science job speeds. I’m not sure how this relates to the current situation with NPC stations v POS v Player Outposts.
From the December patch, depending on how the initial Engineering Complex release works out, the plan is for you to no longer be able to deploy new Outposts or Outpost upgrades. Those that already exist (plus POS) will continue to operate as they currently do.
Speaking of POS – you can plant a small POS for a bit over 100M at the moment (before fitting). It is plausible for you to anchor and remove them solo, and they provide a useful and interesting tool for solo play. So far CCP hasn’t provided anything similar in the move to Citadels.
Evehermit 
Guess what. I will be surprised if they do anything for solo play. There are too many people banging the team up with others drum.
I really like EVE. I have a PVP toon. My industrial and PVE side is when I enjoy down time by myself. Not having to intereact with anyone. I do that in my day job, make hundreds of radio transmissions talking to others. Sometimes I dont feel like doing the same at home.
I suspect they actually think their Citadels are solo friendly. Assuming you plant them in Hi-Sec with no expectation of ever defending or un-anchoring them, I guess they are.
The whole BPOs will go into asset safety thing… any industrialist worth their salt is still likely to have their expensive BPOs locked down in an NPC station (and be copying like mad). The cost to recoup multiple billion iskie BPOs from a downed citadel or engineering complex is going to add up to scary numbers…
I read the article in the hope that it would have some support for the solo industrialist, but nothing there. My alt industrialist is moving towards trade as I don’t think I will be able to operate in the Post Citadel universe.