Citrix XenDesktop 4.0 introduces a number of licensing changes since the last version of Citrix's flagship desktop and application delivery suite, which still apply to XenDesktop 7.6 today.
The previous version, Citrix XenDesktop 3.0 provided a concurrent licensing approach, in line with other products from Citrix such as their XenApp offering. The new version introduces per user and per device licensing options.
The previous version, Citrix XenDesktop 3.0 provided a major leap forward for Citrix in Virtual Desktop Infrastructure (VDI) space, as this version is considered by many to be Citrix's first serious contender in the VDI market.
XenDesktop 4.0 also introduces 'per user' and 'per device' licensing options. This brings this Citrix product in line with other major vendors such as Microsoft, who also use the per user/device licensing approach.
Originally, the 'Per Named User' (PNU) licensing model was advocated to replace the current ConCurrent User (CCU) licensing model, however after feedback from customers that this would make this Citrix product very expensive and therefore unattractive, Citrix bowed to the pressure and utilised a flexible licensing approach with a 'per user', 'per device' and CCU licensing (only in certain editions) being available, with PNU licensing being scrapped.
With 'per user' licensing if there were let's say 10,000 users in an organization who all use Citrix delivered applications and desktops and out of these 10,000, only 2,000 access the Citrix delivered applications and/or desktops at the same time, under the existing CCU licensing, only 2,000 licenses would need to be purchased.
However, with 'per user' licensing there is a shift for each user who accesses the system being licensed, so in this example, all 10,000 users would need to be licensed. If there were only 2,500 devices being used to access XenDesktop but still 10,000 users, then it would make sense to adopt the available 'per device' licensing option.
Citrix is still offering the CCU licensing model but only in the VDI edition, so organisations can pilot the option of going VDI with lower licensing costs.