I updated my ESXi server with Adaptec 6405E from 5.0 to 6.7 in two steps:
– from 5.0 to 6.0 RIAD-datastore was fine
– then from 6.0 to 6.7. On my first try to update to 6.7 I got en error “adaptec driver are not compatible with 6.7”. So I updated the adaptec driver and after reboot I updated to 6.7 with no errors! But since reboot the RAID-datastore offline. The device, storage an partition are shown but not as datastore.
I tried all adaptec drivers, old and new, from adaptec direct and from VMWare, nothing.
ESXi: updated from 5.0 to 6.0 than 6.7.0 Update 3 (Build 16316930)
Controller: Adaptec RAID ASR-6405E KIT | Firmware 5.2-0 
all driver for firmware: 5.2-0 :
I am grateful for every tip!