Hi Dave,
I did exact the same update yesterday at one of my customers.
We had Airwave 8.2.7.1 running on ESXi what is used in managed mode for the instant AP clusters. The update runs seemless!
1. Create a VMware snapshot
2. Create a Backup from Airwave 8.2.7.1 and save it in a save place
3. Upgrade to 8.2.9.0
4. Create a VMware snapshot
5. Create a Backup from Airwave 8.2.9.0 and save it in a save place
6. Upgrade to 8.2.10.1 (it wil still use CentOS6 without issues)
7. Create a Backup from Airwave 8.2.10.1
8. Write down IP settings, dns, gw, etc. i did a export of the certificates and licences keys aswell but wasnt needed afterwards.
8. Turn the server off
9. Do a clean install from 8.2.10.1 OVA template with same IP settings. By re-installing CentOS7 will be installed (our only option).
10. Put your 8.2.10.1 backup back
11. Reboot sytem after completion
12. Your on CentOS7 and Airwave 8.2.10.1, well done!
13. Remove your old server after some days.
All managed devices keep working, licence and certificate where part of the backup restore, so dont need do to that manualy.
Onething! Every version have some "difference" in de update process, the awsftp account, the use of SCP, the /user folder is changed in 8.2.9.0 to some different path /var/ampcli/user. Prepare your self with some SFTP and SCP client/server tools, you will need them ;).
Hopefully this information is usefull for you (and others) and make your upgrade process seemless to!