Migrated from C5 to C8. Easiest migration ever (knock on wood) 
. Hope I'm not jinxing myself. Fantastic job by the Hubitat development team 
I have HOOBS (for integrating a few WiFi devices which I don't want to connect to Hubitat & also retain voice control for them) & Lutron (the Pro2 Hub) in my environment.
My devices are mostly ZWave Plus, Lutron Caseta and a few (three) Zigbee devices.
Followed the steps from the migration document : How to Migrate to a C-8. A couple of additional steps I took:
a. Paused the Hubitat Maker API gateway on HOOBS after I ran a cloud backup of my C5 & shut the C5 down.
b. Shut down my Lutron Pro2 Hub (Power Off 
)
c. Removed the IP address reservation on my network router (for the C5)
d. After the new C8 was connected and powered up, I let it take what ever IP address it got, registered it and restored the cloud back up for migrating my settings
e. After the hub rebooted, went into my network router settings and set up the static IP address which was previously blocked for my C5
f. On the C8, re-enabled the LAN integrations which I'd disabled when prepping the C5 to it's final Cloud backup before shutting it down
g. Went into the C8's network settings and updated the IP address to static and entered the same IP address that was blocked on the network router
h. Restarted the C8
i. Restarted the Hubitat Maker API gateway on the HOOBS box. Didn't have to make any changes to the settings or the API token - they remained the same because of the restore of the settings from the C5 to C8
j. Powered on the Lutron Pro2 hub
Total time taken - less than 20 minutes 
. Everything works exactly like it was, before the C5 to C8 migration. Voice control of all devices via iPhones 
/watches 
works as before. There were a few devices like locks on doors a bit farther away from where the Hubitat is, and a few motion sensors near these locks - they seem to be responding faster than previously. Time will tell if the response speed 
remains the same
