Is the price for the self-hosted license a one time payment?

Yes, you can use self-hosted Kendo manager  for as long as you like without any additional fees. The license also includes one year of support and upgrades, which you can optionally renew.

What does renewing support and upgrades include?

It includes technical support and access to all Kendo Manager upgrades. Renewing is optional and costs $399 per year.