The scale is hard to believe.
Way back, I had the opportunity to tour Chicago's new 911 center. It was humongous in size!
Now they are updating the technology that makes the place run, see Chicago’s 911 emergency center to get a $75 million upgrade.
This is just the software that is being upgraded. The structure itself cost $217M when it opened in 1995. One big lesson they learned over the years is that having software developed as a "one-off" for just them is incredibly costly. Making as big a switch as they anticipate doing in 2020 will be a challenge. Just switching from one version of CAD software to another is hard enough.
I think you can assume there will be some glitches along the way.