[xml] API documentation per version of libxml?

[Jeremy Enos <jenos ncsa uiuc edu>]

Hi-
I used the documentation on xmlsoft.org to write the code I needed for a 
parser.  On my test machine, I had libxml2 2.6.x installed.  Now I'm 
running into requests to make it back-compatible with version 2.5.10.  
Functions like xmlReadMemory, and xmlReaderForFile don't exist in 
2.5.10.  What are my alternative options? 
Is there a snapshot of the API documentation that I could look at which 
dates back to version 2.5.10, or any specific version, for that matter?  
It seems like that would be critically necessary in order to code for it.
thx-

   Jeremy