Prior to October 1st, 2018, Viewer was sold as a perpetual license. On October 1st, 2018, we switched to a subscription model, which means that all new sales are done as subscriptions.
If you are a perpetual license holder, you may continue to use the product perpetually (as the name implies). The only change will be how you are covered under maintenance. Until your maintenance period expires, you are covered under your current maintenance period; nothing changes.
Should you choose to renew maintenance when it expires, you would be switching to a subscription license at that time.
When your maintenance expires, should you choose to not renew maintenance, you may continue to use the product but will not be eligible for technical support and new versions.
As of October 1st, 2018, we no longer sell "full" and "maintenance" licenses. We only sell subscriptions.