The timeline page on wikia for Firefly seems to indicate that Serenity takes place sometime after the TV series, but having watched the TV series and the movie, this doesn't make sense.
Serenity (the movie) opens up with River Tam being sprung from the Alliance facility. I can accept this as a "flashback" but this obviously takes place before the story that takes place during the TV series. However, after the opening sequence during the landing scenes leading up to the first job, the interactions between Simon and Mal do not match up with those at the end of the TV series. It was well established at the end of the TV series that Simon and River had earned their place on the crew of the Serenity - this is stated pretty much in these words by Mal to each of them on multiple occasions.
However, during the first job, River's mind reading abilities are well developed and controlled, which follows on well from the last episode of the TV series.
Furthermore to add more confusion, Wash dies at the end of the movie - so this portion of the movie obviously takes place after the TV show.
With this in mind, where exactly does "Serenity" (the movie) take place during the Firefly timeline?