Hello ,
We are running a esxi 6.0 setup which is a free ware license for testing environment , we are planning to upgrade to 6.7 version .
do let us know if we can upgrade esxi 6.0 to 6.7 directly even if we are running on a free ware license
It is the same, not matter whether you're using a free, or paid license.
Just make sure that your harware is supported, before you start upgrading.
André