After giving it a go in the lab and running into a few issues where the install would roll back (SEE HERE) I decided to also give the fresh install a try. The new install went without a hitch
Everything you need to know
Upgrade
Methods of upgrading vCenter 5.5
Fresh install
Install best practices
Methods for installing vCenter 5.5
Installing vCenter server 5.5 BP
This is the upgrade order directly from vmware. you can find the full article here.
This table describes the sequence in which the vSphere 5.5 and its compatible VMware products must be updated:
Supported Update Sequence
VCD | VCNS | View Composer | View Connection Server | vCenter Server | VR / SRM | vCOPS | VDP | VSA | ESXi | VMware Tools | vShield Edge | vShield App | vShield Endpoint | View Agent/ Client | |
Update Sequence Number | 1 | ||||||||||||||
2 | |||||||||||||||
3 | |||||||||||||||
4 | |||||||||||||||
5* | |||||||||||||||
6 | 6 | 6 | 6 | ||||||||||||
7* | |||||||||||||||
8 | |||||||||||||||
9 | 9 | 9 | 9 |
* If using a Cisco Nexus 1000V, see vSphere 5.5 and its compatible third-party products in the Additional Information section of this article before upgrading the vCenter Server (sequence step 5) or the ESXi hosts (sequence step 7).
Note: If you need to update multiple products in your environment, start with updating the product with the lowest sequence number. After you update the product, update the product with the next sequence number. If a product is not present in your environment, update the subsequent product. If you need to update two products with the same sequence number, the order of update does not matter.
Before you update the vCenter Server, disable vCenter Server from vCloud Director. Also ensure that you stop or disable other VMware services so that they do not communicate with vCenter Server during the update process. For more information, see the product documentation.
You really need to verify that all the products you are using will be supported. my lab is limited and I could not check any alternate configurations other than those set aside in the upgrade and install guides.