> Follow the strangler fig pattern, and map out every single task that is required in the migration on a whiteboard. > Write tests if you can, and set up a sta

> Follow the strangler fig pattern, and map out every single task that is required in the migration on a whiteboard. > Write tests if you can, and set up a staging environment for V2 that you can setup and tear down easily for battle testing way before going live. I've successfully helped migrate a critical project and followed exactly this strategy. Older versions were being developed and run 1:1 in parallel to the newer ones until the customers got only a small downtime due the change of IP Addresses were the system was running