How can I determine what flash player version a swf was published for?

Question

I have a SWF of unknown origin, and I need to know which flash player version it was targeted at when it was published. How do I get this info?

Answer 1

The 4th byte in the SWF file carries the version number, for example 0A is for Flash Player 10.

EDIT: Because of the high interest this question got I've decided to give more feedback

The first 8 bytes of any SWF file are not compressed, the rest of the file could be compressed (or not) by zlib compression.

• 1st byte: 'F' (not compressed) OR 'C' (compressed).
• 2nd byte: 'W' always.
• 3rd byte: 'S' always.
• 4th byte: version number (09 means this file is targeted at Flash Player 9 and so on...)
• 5th to 8th: Length of entire file in bytes.