some questions about sending data

-Is data send over from client to server or vice a versa guaranteed to arrive ?
-does it arrive in order ?
-can you define wheter it's important that it arrives
-can you define to ignore a message when there's already a more recent one ?

I guess they arrive in chronological order, but it could depend on the message size and other stuff.
If you only want newer messages and ignore the older ones, you could add some kind of tick variable that increases with 1 for every message and send that with it. If the variable is higher than that in flash at arrival its outdated. Or something like that o.O

1. Yes
2. It should, but don't rely on this while programming.
3. NA, read above.
4. This could be programmed in with simple timestamps sent with the messages.

Hope that helps. :)