[Zope-dev] Future of ZClasses

I found a thread (from March 2006) discussing the future of zclasses, but i could not determine if a 'final' decision had been made. According to Changes.txt for Zope 2.10.0: "ZClasses are deprecated and should no longer be used. In addition any code related to the ZClasses (re)distribution mechanism is removed." Does this mean that any application which incorporates zclasses will break if upgraded to zope 2.10.x? The reason i ask is that i have a huge legacy system (zope 2.6) that is about to be upgraded to a more current version of zope, and i am wondering if this is the time to replace the zclass utilization (a seriously non-trivial task!). Thanks, Jonathan