title: Are Python 2.5 .pyc files compatible with Python 2.6 .pyc files?
body: <p>A while ago I had to upgrade some servers from Python 2.4 to Python 2.5. I found that .pyc files created under Python 2.4 would crash when Python 2.5 tried to run them.</p>
  
  <p>Will this happen again when I upgrade from 2.5 to 2.6?</p>
  
  <p>EDIT: Here is a bit more detail</p>
  
  <p>I have a fileserver that contains the python code. This is accessed by both Ubuntu and Windows servers to run the python code. When they run the code they produce .pyc files on the fileserver.</p>
  
  <p>I found that when I upgraded one of the server machines from Python 2.4 to 2.5 I had problems with .pyc files. I'm now not sure whether it was a machine running 2.5 that tried to run 2.4 bytecode or whether it was a 2.4 machine trying to run 2.5 bytecode, but if I deleted the bytecode all went well until the next bytecode clash.</p>
  
  <p>I upgraded all of the machines to 2.5 and the problem went away.</p>