Best practice to upgrade SEP 11.x clients to SEP 12.x

Hello everyone,

Scenario: SEPM 11.x just migrated to SEPM 12.1.2015.2015

I have a group of SEP clients running SEP 11. I sync those SEP 11 clients with SEPM 12

Now, I'm looking for a best way (or best practice) to upgrade those SEP 11 clients to SEP 12 clients

I would like to know if:

1. Upgrade SEP 11 clients to SEP 12 means "installing whole client package again"???

2. Upgrade SEP 11 clients to SEP 12 requires "reboot"?? (Probably it will, just wanna be sure!!)

3. Any situation or problem i could face during this migration???

Thanks in advance :)