I've heard thet vmtools 12.x has been released, the is that i can't find it in my vsphere interface to start upgrading VMs.
is there any action that i should do (update vcenter or something like that)
thank you in advanced
The question is what ESXi version and build do you have?
You can upgrade ESXi hosts itself and new VMware tools will be automatically recognized by the system or you can use vLCM and upload VMware tools there, sometimes this second option is a bit risky.
I would recommend you update all your ESXi hosts to the newest/latest version. I mean 7.0.3g
But first, update your vCenter to build 7 U3h, after that - ESXi hosts - with this update you will have the latest VMware tools.
This is a win-win situation.