12:38 AM
Someone with a computer should check if it's a bacon cipher after that hint

1 hour later…
user189275
2:02 AM
@ffao: There are atleast 6(Take the first, vertical is A/B/Take the last, vertical is A/B/Total number of notches) * 2(Horizontal/Vertical) *4(IJ same/UV same/Both/None)*2(Interchaging AB) *Someother I'm missing, so around 100 possibilities, and I'm too lazy to check that.

user189275
It could be polybius too.

user189275
4:41 AM
Oh I am stupid, the "IIIII" suggests that it can't be polybius.

5:25 AM
@ArbitraryKangaroo You are over-complicating it.

2 hours later…
7:41 AM
@ffao slowly tapping it out on mobile... I FOUND HER...

user189275
@Alconja: You found it ?

user189275
Who is "her" ?

Don't know. But the full message is: I FOUND HER. I FINALLY FOUND HER.

user189275
@Alconja: How ?

Baconian - vertical line = A, horizontal = B (with the I=J version of baconian)

user189275
7:50 AM
@Alconja: Now, Part 7 is still left.

Yeah. No time to look right now unfortunately. Just stuck my head in briefly to see how things were progressing...

user189275
8:30 AM
@Alconja: If you overlay the two letters, ERRIO are the letters that match. Most probably a red herring, though.

The rest of the puzzle has nothing to do with ciphers anymore. You need to interpret the information scattered throughout the puzzle.

user189275
@Sleafar: Oh, so may be some meta cipher (or something like take the nth letters/word/something else of the previous picture's transcript) with the previous pictures.

@ArbitraryKangaroo Quote: "has nothing to do with ciphers anymore"
neither steganography

user189275
@Sleafar: So we have to find a pattern with the dates ?

That would be a good start
Updated the question:
- If you think, that you don't have enough different dates yet, there is one unused hint in part 2.

user189275
8:43 AM
- Remember the history tag. ?

In the original puzzle.

user189275
@Sleafar: Like there was an (till recently; Alconja solved it) unused hint in #6

Yes.

2 hours later…
user189275
10:29 AM
@Sleafar: So no more imgur links this time ?

Correct.

5 hours later…
3:55 PM
Recapitulating, we started in 2016, got a letter from 1969, then went back to 1908 and read an article in a journal published in 1827-1829, went back to 859 then to 75 BC, where we saw a message that said "I found her. I finally found her."
I'm not good at making heads or tails out of this sort of thing, so I'll wait for someone else to enlighten me

4:30 PM
@ffao You missed some numbers.

5 hours later…
9:16 PM
Oh, I forgot 1404 in part 4
And part 3 was 1722