F5 VPN SSL migration

Hi,

We have our F5 4000 platform that will be migrated.

we have 2000 VPN SSL users , and reverse proxy / Load balancer

I would like to have any idea for these migration.

Could we migrate all users at the same time? how can we process?

Public addresses also change for VIP how can we take in account this change.

Since new F5 will be install, could we export ucs config file and import it on the new one?

Thanks for your help and for your quick reply

Regards