E-mail server is an important infrastructure in all enterprise and company. Technology goes on and never stuck in pause, so also Companies need to still in step with technology.
Many Companies are afraid of changed and they are worryed to lost data.
Now we have all technologies that can migrate your infrastructure in totally relax without lost data and without downtime.
In my 15 years old experience i've seen many migration scenario and make a lot successufull migration project without lost data.
We can migrate Exchange server in same infrastructure or in different infrastructure, in crossforest mode. I am confident that you can migrate your Exchange without worryes if you trust in me