What is the reason glibc is at version 2.3 for etch?

[Lex Hider <floss@lex.hider.name>]

Hi,
I've been discussing with some #fluendo people about their codecs not being 
compatible with etch (requires glibc 2.4+).

Can anyone give a brief answer to why etch will be shipping the glibc at 2.3.
I couldn't provide an explanation as to why it is only 2.3 being shipped.

Thanks,
Lex.