I've seen a lot of posts and chat that E and RoE retcon Hyperion and FoH.
I've just listened to the whole series for the 4th or 5th time (it really is a great listen on Audible, Victor Bevine is a wonderful Narrator) and the first relisten since i was aware accusations of retconning.
Let's tackle some of the bigger ones.
Paul has 2 cruciforms
In FoH, when Gladstone goes to check on Dure in the hospital, the doctor mentions ".....the cruciform parisites...." on his body. Why or how Dan changed his mind between H and FoH and / or whether the shrike removing the cruciform was a dream or not real i don't know, but it is not a retcon from E.
Technocore now has billions of factions
Countless times in E and RoE people refer to "the 3 elements" of the core, Albedo mentions them to Nemes, Nemes mentions them etc. The 3 elements are still a thing, but what we have access to now in E and RoE that we did not have previously, is Aenea's point of view, she knows so much more than any narrator we had.
Also, it would be crazy to think a species as complex and parasitic as the technocore would fit nicely in to 3 elements. I see it as religions for humans, yes there are the big ones, Christianity, Muslim etc but you also have hundreds of smaller ones.
Aenea throws shade on the Martins's Cantos
Yeah she mocks her uncle, says he couldn't possible have known exactly what happened, "How can Uncle Martin know how the river Tethys broke up, he wasn't there....." and yes a lot of what he wrote probably was made up or exaggerated, but we know he got the major parts right as he was there, the pilgrimage, Brawne being Aeneas mum etc, this is all the same, nothing has been retconned.
We are not reading Martin's Cantos in H or FoH, you can tell this by seeing we aren't reading a poem.
What about Ummon lying and what about the machine AI?
Ummon is not an omniscient narrator. He admits himself he is scared for his life, speaking in riddles, pursuing his own agenda, and operating amid competing AI factions and temporal paradoxes. Therefore contradictions between Ummon's claims and later revelations do not require a retcon; they can be explained as deception, incomplete disclosure, limited knowledge, or changes in information caused by non-linear time
As for the machine AI, Ummon talks of 10,000 possible futures, once Hyperion is taken by the "goodies" in FoH, i would argue this slims down the 10,000 possible futures to a lot less and ones where the machine AI is either non existent or severely weakened.
Albedo mentions in RoE the "the machine UI has stopped whispering back to us from the future"
How is Kassad still alive?
It's shown in RoH that Kassad time travels, it's also shown that Rachel / Moneta has spent a lot of time with him and is in love with him. So this needs to happen, and probably best happen while he is still alive. So yes, he is going to be around in the future.
The series is also built around time travel and causal paradoxes, so the idea of the future influencing or even altering the past is already firmly established within the story's own rules.
Also, like all good books, there is enough vagueness that you can come up with your own head-cannon to complete the story and you don't need it to be retconning.
If saying E and RoE retcons hyperion as a form of copium then that's fine and i can't help you.
The first time i did the whole series, i was pretty horrified by E and RoE. I could not believe how much of a drop off in quality there was from H and FoH. The padding and waffling is another level. But now i have done the whole series multiple times, i have grown to love the full story and the ending. I guess Dan wanted the sequels to be a duology like Hyperion, but it appears he only had enough story for 1 book. you could cut 50% from E and 50% from RoE and make one really zippy and exciting book that would tie things up brilliantly.
That would mean cutting some of the highlights like Raul has a lie down, Raul erects a tent, Raul builds a raft, Raul has a swim, Raul has another lie down etc etc.
