If everything is in place for a planned upgrade, but the system is delayed until after the relocation, users are able to retain continuity in their work. There are exceptions to this however, including networking gear, and re-IP, as they do not have a great impact on the software and easier to perform during the move.
Choose and experienced professional for the move. Each department is specialized, and while you may assume IT fully understand the system, they may not have all the knowledge required to successful move and reinstall it.