As a show whose fandom exploded in popularity very early on, before many plot developments, My Little Pony: Friendship Is Magic naturally has a lot of fanworks that have been Outdated by Canon.
- Antipodes: As the story was written and drafted partway through Season 1, before the majority of the show's run and consequently before the introduction and exploration of several characters and setting elements, a lot of the fic's own elements show their age:
- The core premise of the story is that, with Princess Celestia and Princess Luna gone, the sun and moon can no longer be moved and remain permanently fixed in the sky, burning one side of the world and freezing the other. Show episodes that aired after this story came out established that the celestial bodies can be moved just fine by other beings, including groups of unicorns working in concert.
- The basic idea of Celestia and Luna being transcendent Physical Goddesses older than the world also became distinctly dated, as alicorns were eventually established as being essentially just very special ponies and the two princesses as themselves not being very magically powerful outside of specific contexts, in addition to not being much over a thousand years old.
- Bubbles depicts Derpy Hooves as developmentally and physically impaired. Her later canonical characterization has her as a ditz with some vision impairments due to a lazy eye.
- Claro de Luna was written prior to "Luna Eclipsed" and depicts Luna as a slightly shy, adorkable mare with a short mane (like her season 1 design). It also features ponies that age like actual horses instead of comparable to humans.
- The song "Crusade No More
" by Replacer, uploaded in 2012, is about the Cutie Mark Crusaders getting their Cutie Marks and splitting up, as they have more important things to do now that they no longer need to try different things in search of their special talents. Come season 5, the CMC get their Cutie Marks in canon, and they get them at the same time, with their special talents being to help other ponies with Cutie Mark-related issues, which requires them to keep working together. - As Cutie Mark Crusaders 10k began during season 3 of Friendship is Magic, several elements contradict information established later in the show's run:
- The Cutie Mark Crusaders' Cutie Marks are all drastically different from each other instead of having the same base shield with differing emblems; Apple Bloom has a mug of cider, Scootaloo has a scooter, and Sweetie Belle has a pair of bells.
- Trixie's magic aura is red regardless of whether the Alicorn Amulet is affecting her powers; later episodes make it clear that the red is a side effect of using the Amulet and her natural magic color is pink.
- As an adult, Spike has a lanky build instead of his bulky one from the series finale.
- While the Changelings have performed a Heel–Race Turn and gained more individualistic appearances, the former event didn't lead to the latter happening like it did in "To Where and Back Again"; the Changeling drones gained their distinct looks after getting into the hive's supply of royal jelly, then joined forces with the ponies. Additionally, the redeemed drones look the same as they did before except for having hair and Chrysalis' eyes instead of being colorful beetles.
- Darkest Before Dawn depicted the young Twilight Sparkle as an only child, but "A Canterlot Wedding" revealed that she has an older brother, Shining Armor. The author originally planned to do more "books" chronicling each school year, but canceled it after finishing Year 1 because of this.
- Dash's New Mom centers around Rainbow Dash's widower father getting a new girlfriend, and Rainbow's reaction to the event. After the fanfic's completion, "Parental Glideance" revealed that Rainbow's mother is still alive.
- Kindness's Reward has this in several fashions:
- The story predates the IDW comics canonizing that Trixie grew up with a single mother. Kindness's Reward depicts Trixie as growing in an orphanage until she ran away.
- The story revolves around Fluttershy taking in a deathly ill Trixie. Later episodes confirm that Fluttershy's medical skills apply only to woodland animals, not ponies.
- The plot begins with Trixie being lost in the Everfree Forest for weeks. The series later showed that Trixie actually went drifting and ended up working on the Pie's farm for a while.
- Lullaby for a Princess depicts Celestia versus Nightmare Moon. It was animated prior to the official version and deviates in many manners. For example, Celestia had a pink mane in the animation that changed colours upon using the Elements of Harmony, but in canon Celestia had her current mane even back then. The fight is also more action packed and dramatic than the official portrayal. Celestia breaks out in tears at the end of the battle. In canon, Celestia does shed tears but it's a far more subdued reaction than in Lullaby for a Princess.
- The Moon Rises depicts Starswirl as being around during the Nightmare Moon incident. Later episodes revealed that he was long gone by then.
- Patience, She Said has Spike on the last day of his life roughly a thousand years after all his friends have passed away. In "Campfire Tales", Torch is shown as a fully grown dragon in Rainbow Dash's story about Flash Magnus, which takes place over a thousand years prior to the series, while in the present he looks to be not that far into his middle ages. This pretty much confirms that dragons live much longer than a thousand years.
- In Princess Trixie Sparkle it is revealed that Starswirl the Bearded turned into and is now trapped as the Tree of Harmony. While season 7 did reveal a connection between Starswirl and the Tree, he seeded it (with the other Pillars of Equestria) rather than morph into it. He was, however, trapped in Limbo afterward.
- Progress uses Luna's design from the pilot and depicts her as an adorkable Fish out of Temporal Water.
- Strangers features an older Sweetie Belle. It predates Sweetie getting her Cutie Mark and thus it uses her G3 mark instead of her canonical G4 one.
- The webcomic Time Fades has an elderly Spike recounting the lives of the Mane Six and himself up to their deaths. It came out around the time of Seasons 6 and 7 and so contradicts those seasons and the Grand Finale in a few ways:
- None of Spike's lanky adult forms resemble his beefy adult form in canon.
- Twilight remains in her normal body proportions. The Distant Finale shows her grown into Princess Celestia's proportions.
- The Changelings war with Equestria. In canon, they reform and become allies before any such conflict. They also get new forms.
- Twilight becomes ruler of Equestria after Changeling impostors kill Celestia and Luna. In canon, Twilight became ruler after the Princesses retired.
- Queen Chrysalis' final fate involves her being murdered. In canon, her final fate was to be turned to stone.
- Prior to becoming Captain of the Wonderbolts, Rainbow Dash loses a wing during the war with the Changelings and is forced to wear a metal one for the rest of her life. While the fic predicted that Dash would join the Bolts and eventually become Captain, she had both wings intact as of the Grand Finale.
- The Vinyl Scratch Tapes has Vinyl tear into Princess Celestia for banishing Luna to the moon. Almost all of her arguments were Jossed both by Word of God and canonical episodes, to the point a later chapter has Luna explain in detail to Vinyl why she was wrong.
- 2015's When the Bough Breaks revolves around Cadance and Shining Armor having a stillborn pegasus son. They would later canonically have an alicorn daughter.
- Why Am I Crying? was written prior to season 5 episode "Crusaders of The Lost Mark" and so contradicts that episode and some others, besides Diamond Tiara not dying before that season and surviving into adulthood:
- Diamond Tiara's mother is revealed to be dead having passed away due to complications with the pregnancy of Diamond Tiara's little brother, and her name was Crystal Eyes. In canon, Diamond Tiara is an only child and her mother's name is established as Spoiled Rich who's shown to be very much alive and unfortunately nowhere as nice as Diamond Tiara's mother in the story was implied to be.
- The Cutie Mark Crusaders are implied to have gained their Cutie Marks separately (it is mentioned Scootaloo got hers last). In canon, the Crusaders gained their marks at the same time.
- Diamond Tiara's Cutie Mark is explained to represent a desire to be like her mom - a model. In canon, Spoiled Rich is not a model and the Cutie Mark was revealed to represent Diamond Tiara's skill of leadership.
- The fic shows that Scootaloo lives with her father, who is divorced from his wife. The Season 9 episode "The Last Crusade" revealed that Scootaloo lives with her aunts while her parents, who are still together, work abroad.
- The final chapter, where the CMC are adults, has a future version of Ponyville that has Twilight still living there. In the show's Grand Finale, Twilight returned to live in Canterlot while the CMC were still children.
