KB

Collecting diagnostic information for VMware ESX/ESXi
Collecting diagnostic information for VMware vCenter Server 4.x, 5.x, 6.x and 7.0
Uploading diagnostic information for VMware

Best Practices for upgrading to vSphere 6.5:
vSphere 6.5 Upgrade Guide
Guide de mise a niveau vers vSphere 6.5
Mise à niveau vSphere 6.5

Best practices for upgrading to vCenter Server 6.5

ESXi:
Hardware status is displayed as "unknown" for certain sensors on ESXi host
EVC and CPU Compatibility FAQ

vCenter:
How to reset the lost or forgotten root password in vCenter Server Appliance 6.5 & 6.7
"invalid credentials LDAP Error Code 49" error when starting Inventory Services in vCenter Server 6.x
"WARNING: VMware ESX Agent Manager may have failed to start", EAM Service fails to start after vCenter Server reboot