Incompatibilities in upgrading to libc6 2.5

["John Zoidberg" <the.real.doctor.zoidberg@gmail.com>]

Hi,

I'm running a Debian system with glibc6 2.3, but I'm "stuck" (i.e. I'm
unable to install TeX and friends) unless I upgrade to glibc 2.5.
This would be no problem if I didn't have to run commercial software
(including a cross compiling toolchain) that was dinamically linked to
glibc 2.3.

I could try upgrading, but if I lock myself (i.e. become unable to run
the commercial software), I don't know how to revert to glibc 2.3.

So, does all the software linked to 2.3 also works with 2.5?

Thank you for your attention.