Question

What new information is learned about district 4 through Octavia’s complaints

Answer 1

The problem of District 13 worries Katniss, but there's nothing she can do about it.
Months pass and it's basically spring by the time Katniss' prep team arrives to help her get ready for a pre-wedding photo shoot.
At one point Octavia complains that seafood from District 4 isn't available. Octavia gives a lame reason for the seafood shortage, but Katniss sees right through it. She is convinced that this means there's trouble in District 4, and that the Capitol is hushing it up.
Katniss attempts some delicate questioning. She thinks it's possible that the people in District 3 are also stirring up unrest against the Capitol.
Cinna and Effie arrive to help put on Katniss' makeup before her photo shoot.
Katniss poses for hours and then everybody leaves. She's left with her family, feeling absolutely wrung out.
That night she has terrible dreams.
The next day she wants to decompress by talking with a trusted ally, but she's not sure whom to turn to. She settles on Haymitch and fills him in as quickly as she can.
He has news, too. Between the two of them, they think about half of Panem is ready for rebellion.
Haymitch gloomily says that 12 shouldn't rebel; otherwise they could end up like 13. He doesn't buy the possibility that 13 has secretly rebuilt itself.
Later that day, they find out they have to watch a special program on TV that night, by government order.
Prim says it'll be the wedding shoot. Katniss worries about what this will mean for Gale.
There's a whole program about people getting to vote on which dress Katniss will wear for her wedding.
After the program, the announcer, Caesar Flickerman, explains that the next Hunger Games will be the 75th. That's a special anniversary marked by a Quarter Quell, to reinforce the whole purpose of the Games.
Snow appears to explain what will happen at this Quell. At the first Quell, the districts had to select their own tributes through an election process. At the second, twice as many tributes had to go.
Snow has to open a little card to explain this Quell, since the form of it is (supposedly) a surprise to everyone. He reads out that in this third Quell, the tributes will be people who have emerged victorious from previous Games.
Katniss' family catches on to this bad news more quickly than she does. Even though she just survived the Hunger Games, now she's going to be thrown into the arena all over again.