Upgrade of Xalan 1.2.2 and Xerces 1.4.4 to Xalan 2.6 and Xerces 2.6.2

[cvissy]

I've been tasked with upgrading the JVM from
1.3 to 1.4, and the third party libraries used
by my company on our existing Java framework.

I'm most worried about any problems that may occur
due to upgrading Xalan and Xerces as our framework
performs much XML transformation and processing.

Does anyone have a link to known issues with such
an upgrade (besides the Xalan / Xerces sites) ?

Or has anyone done such an upgrade and can share
their pearls of wisdom?

Thanks
Chris