By purchasing HelpDesk for SharePoint 2013/2016/2019/SE you achieve a perpetual license. One license is linked to one Web Front End server (WFE). You need to purchase as many licenses as WFE servers you have. Find more information about WFE servers in in this article . The license includes one year of updates and Standard Support Plan. The license is perpetual, but you can renew it to get one more year of Standard Support Plan and updates. You can purchase renewal from your shopper account.
By purchasing HelpDesk for SharePoint 2013/2016/2019/SE Development version you achieve a perpetual license. One license is linked to one development or test Web Front End server (WFE). You need to purchase as many licenses as WFE servers you have. The license doesn’t include updates. The development version once per 100 messages instead of regular email notification sends an email with a predefined text about the development license.