If you are consultant and working for a company on hourly basis, stop here and try a slightly longer method using GUI ☺
Open PowerShell with administrative privileges
1. Execute following command on Server 2012 R2 to save data including scope, reservations and leases etc.
Export-DhcpServer -File C:\DHCPMigdata\DHCPdata.xml -Leases -Force -ComputerName old.network.local.server2012R2 –Verbose
2. Execute following command on Server 2016 to copy an existing data
Import-DhcpServer -File C:\DHCPMigdata\DHCPdata.xml -BackupPath C:\DHCPMigdata\ -Leases -ScopeOverwrite -Force -ComputerName new.network.server2016 –Verbose