I just noticed that there is a new firmware available from DIGI for the XBeePro 900MHz radios.
The new firmware #1061 has added a choice for 1 or 2 stop bits for serial I/O.
New sleep functions , could be useful ground-side but not likely needed.
There also are some new network node functions.
There are 3 more diagnostic commands and there are functions for I/O sampling.
I haven't read though the updated manual, yet, but I hope to get to this weekend if the weather keeps me from flying.