LOL, sounds like my workplace. Last 14 years I was there I worked a 'temp 6 month changeover' going from a DOS system (yes, in 2009) to not one, but two systems that DID NOT communicate with each other (mainly because financial side wanted to 'see' everything and the actual machine/field side thought that system was too complicated). An interface was built to do the hand-offs, but it NEVER worked right and was a pure disaster at the first location down in Texas when we went down to put it online. That '6 month project' I rode out on until I retired, it did get slightly better the last 3 years, but wow. The 'savings' claimed by the folks that came up with that cost each location a minimum of four new people/positions to babysit and fix the errors/failures.