A Guide to Classic Who references in New Who episodes.
The eleventh episode of series 8, part one of the series final.
Warning: May contain Spoilers for
- 7-06 "The Bells of Saint John" (Suggested viewing - reintroduction of character, plot connection)
- 8-01 - "Deep Breath" (Suggested viewing - reintroduction of character.)
- 8-02 - "Into the Dalek" (Suggested viewing - introduction of character, plot point.)
[1ST] - First appearance in Doctor Who.
[NEW] - Stuff seen previously in the New Series.
[OLD] - Things that first appeared in the classic series (or the film.) Episode List.
[OTH] - Specific references to material beyond the shows themselves (Books, Comics, AudioPlays)
[INJ] - In-jokes.
- [NEW] Notes - The post-it notes are all the things that Clara feels she needs to tell Danny, and a mostly about her time with the Doctor, especially since she met him ("Into the Dalek"). I've indented them all here so you can skip past them because they're all pretty obvious.
- The Doctor - The Doctor.
- The Impossible Girl - What the Doctor called Clara and her echoes before he knew what they were because he kept seeing her die.
- Vastra/Jenny - The female 66.7% of the Paternoster Gang. Clara Oswald met them in "The Crimson Horror," "The Name of the Doctor," and "Deep Breath." Clara echo Clara Oswin Oswald had previously met them in "The Snowmen" but Clara Oswald probably doesn't remember that.
- Half-Face Man/Dinosaur in London - Appeared with Jenny/Vastra in "Deep Breath" before Clara met the Danny.
- Miniature Clara - A reference to "Into the Dalek"
- Robin Hood - Turned out not to be the "Robot of Sherwood."
- Rupert Pink/Dan, Dan the Soldier Man/West Country Care Home - Clara met young Danny when he was still called Rupert and implanted the image of Dan the Soldier man in his head in "Listen."
- Rob the Bank/Psi/Saibra/Karabraxos/The Teller - Let me point you in the direction of "Time Heist" for all of those references.
- Kill the Moon/Courtney on the Moon/Courtney becomes President/Blinovitch - First two references to the plot of "Kill the Moon," the second are the Doctor's claims about Courtney's future from the same episode.
- Orient Express/Maisie - References to "Mummy on the Orient Express."
- Boneless - The name the Doctor gave to the two-dimension beings in "Flatline."
- Lying (twice)/Truth/Just Say It - General references to her behaviour and their upcoming conversation.
- Three Months - Don't know specifically what this means, possibly the time she's been with Danny and withholding information about the Doctor.
- [OTH] Hyperspace Body Swap Ticket - The ticket on Clara's shelf appeared in the mini-episode created for the 2013 Doctor Who Prom. The Eleventh Doctor explained that by scratching the "scratch here" two people would be deleted and Clara and the Eleventh Doctor would appear in the deleted audience members seats. The deleted people are compensated.
- [NEW] Photo of Clara's Father & Baby Clara - From a scene from "Rings of Akhaten."
- [NEW] Clara's Grandmother - Previously appeared in "The Time of the Doctor."
- [NEW] The Doctor's Caller ID - In "Mummy on the Orient Express" Clara had a stick insect to represent the Doctor, now it's a generic "no image" picture.
- [NEW] The External Phone - Clara is still using the Door Phone (or the console phone has routed back again.)
- [NEW] Active Volcano - The Doctor visited one in "Fires of Pompeii."
- [OLD] TARDIS Key - Obviously, the key to the TARDIS. It has appeared in a number of forms and in some cases could only be used by the Doctor. The Doctor gave one to Rose in "Aliens of London." It hasn't previously been stated that lava will destroy them.
- [NEW] Sleep Patch Things/Dream State Patches - Possibly a mood patch like those from "Gridlock."
- [OLD] Cloister Bell - A warning bell that sounds within whenever the TARDIS or the universe (or both) are in significant danger. Here it sounds once when the first and last TARDIS keys are thrown into the lava.
- [OLD] Changing Timelines and Paradoxes - As mentioned previous and changing thing touched upon regularly in the new series and gone over again here.
- [NEW] Nethersphere - Previously recurring place in this series. Seb appeared previously in "The Caretaker."
- [OLD] The TARDIS's Telepathic Circuits - Usually used for translation, but used for navigation a few times in the new series, especially exactly this way in ""Listen."
- [NEW] Killed Anyone? - Danny was asked about this in his first appearance in "Into the Dalek"
- [1ST] X-Ray Water/Dark Water - First appearance of this substance.
- [1ST] White Noise - First time this theory's been mentioned in Doctor Who, but it relates to the ghost-hunter's theories of Electronic Voice Phenomenon and has appeared in other fiction.
- [OLD] The Cybermen - Recurring enemy from the original series.
- [NEW] Far-Future Cybermen - These Cybermen appear to be of the same design as the far superiour models that almost wiped out humanity in the far future and first appeared in "Nightmare in Silver."
- [OLD] Cyberman Under Glass - Visual homage to the Cybermen breaking free in the Second Doctor story "Tomb of the Cybermen."
- [OLD] 23rd November - Clara Oswald and at least one of her echoes (Clara Oswin Oswald) share their date of birth with the date of the first broadcast of Doctor Who.
- [OLD] Matrix Data Slice (Gallifreyan Hard Drive) - The Matrix was the Gallifreyan Super Computer that appeared in reality imitating worlds or black void, usually accessed by a something placed on the head, including the Crown of Rassilon.
- [OLD] Abandoned Time Lady - Although the episode later reveals Missy's identity, number of Time Ladies appeared in the classic series (and some in the new one). Missy may have been messing with the Doctor's sense of guilt over any of them that he considers he abandoned: Time Lady's in his life when he fled Gallifrey, his granddaughter Susan who the First Doctor ("The Dalek Invasion of Earth") locked out of the TARDIS and forced to stay in the 22nd Century (she later appears on Gallifrey again in the Fifth Doctor story "The Five Doctors") although she was never referred to as a Time Lord or Time Lady, Romanadvoratrelundar his companion who didn't want to return to Gallifrey and remained in E-Space (The Fourth Doctor story "Warrior's Gate") or The Rani, a classmate and enemy of the Doctor who was last seen trying to escape in her TARDIS only to be kidnapped by bestial aliens called Tetraps. There is also the unnamed female Time Lady who helped Wilf in "The End of Time" (written as, but not stated to be, the Doctor's mother) who was in the link between Earth and Gallifrey that the Doctor broke, theoretically sending them all back to the Time War. Any Time Ladies in his life on Gallifrey during the Time War when he did what he did to end it. So, pretty much any Time Lady at varying levels.
- [INJ] Daleks and stairs - Daleks were explicitly shown levitating upstairs in the Seventh Doctor story "Remembrance of the Daleks" and the Ninth Doctor story "Dalek."
- [OLD] Cybermen leave St Paul's Cathedral - Visual reference to the Second Doctor story "The Invasion."
- [OLD] The Master - A childhood friend and long-time nemesis of the Doctor, who seemed to have last appeared in "The End of Time part 2." Turns out, she has been appearing all this series. For the Master in the Classic series, see FOES - the Master.
- [1ST] Change of sex on Regeneration - Hasn't been shown officially (but did appear in the BBC made charity parody "The Curse of Fatal Death" written by Steven Moffat in which the 13th Doctor was a woman. The Eleventh Doctor at first thought his long hair was a sign he might be a girl ("The End of Time Part 2") and noted that the Corsair was a herself a couple of times
10. The TARDIS is for arriving at the location of the story at the beginning of the episode and leaving at the end. This is because Time Travel is the excuse for the story, not that the story is about. Unless the episode is written by Steve Moffat, then it's definitely about Time Travel.
The TARDIS is used just for travel and refused to be used to change time. There is an attempt to use it to enter the afterlife. However, it is a Moffat episode. [.5]
9. No one can cross their own Time Stream, except when they do.
No one does, even though Clara demands they do. [.5]
8. There's no situation that can't be briefly defused by a non-sequitur.
The Doctor, not so much, this episode. Missy, however... [.5]
7. The Doctor is both the most serious and most frivolous person in the room - any room - at the same time. And he does that without becoming insane. Mostly.
The Doctor, not so much, this episode. Missy, however... [.5]
6. The last episode of every series must contain the Master or at least one Dalek. Every time. However briefly.
This is part one of the series final. It does include the Master. [.5]
5. The main companion will be a young contemporary British female. Although, to be
fair, almost everyone in the Universe is British and most things happen in contemporary London.
Clara is a young contemporary British female. Although it seems otherwise, most of the episode occurs in contemporary London. 
4. The more emotionless a species, cyborg or robot the more likely they are to be destroyed by emotions. This is true of the Daleks. It is particularly true of the Cybermen.
The Cybermen appear. Their removal of emotions is mentioned, but they appear late in the episode and are not yet defeated. [.5]
3. Even if the episode title contains the words "Dalek(s)" or "Cyberman/men" the presence of the Daleks and or Cybermen will at the beginning be treated as a mystery and their revelation a surprise.
Cybermen do appear, but the title doesn't spoil that. Photos from the location shoot and the "next time" ad did. The title "Dark Water" doesn't really spoil anything. 
2. The nature of the threat will be revealed to the audience before the Doctor. The truth behind the threat will be unknowable by the audience until it is explained by the Doctor.
Missy first appeared episodes ago. The Cyberman doors were shown to the audience before the Doctor worked it out. The Doctor was given information about Missy before the audience but still didn't work it out and had to be told. 
1. The most dangerous creature in any situation is the last of its kind. This sometimes also applies to aliens other than The Doctor.
The dangerous creature is the second last of his kind and makes the Doctor the second last of their kind also. [.5]