When I try to load a file into Tecplot 9 I get this message:
Binary file version newer than Tecplot version. Upgrade Tecplot or use an older preplot to produce the data.
The binary file format has been changed with Tecplot 10. If you save a binary file from Tecplot 10 or create a binary file using the current TECIO then try to load the file in Tecplot 9 or an earlier version you will receive this message.
If you open the binary file in a text editor the first characters indicate the version. If it says #!TDV10 it is in the Tecplot 10 format.