Citrix started its life as Citrix MultiUser and then WinView for OS2. Then Microsoft came up in the world and WinFrame was born. Winframe grew until it became Citrix Metaframe 1.8.
Metaframe 1.8 became Metaframe XP. One of the big improvements in Metaframe XP was the consolidation of all the Metaframe 1.8 consoles into the sing Citrix Management Console (CMC). The CMC is what we would (2007 / 2008) refer to as the Presentation Server Console.

Metaframe XP had its additions in the form of Feature Releases (FR) – Metaframe XP FR1, Metaframe XP FR2 and Metaframe XP FR3. MetaFrame FR3 has the Program Neighborhood Agent Admin Tool feature with no more manual editing of XML files.
Metaframe XP then made way for Citrix Presentation Server 3.0. Presentation Server 3.0 saw the birth of the all new and improved licensing strategy and Access Suite Console.

After Presentation Server 3.0 came Citrix Presentation Server 4.0 with the new Isolation Environments features. It was around this time the Citrix decided to brand many of their other products to the version 4.0 convention.
Presentation Server 4.0 Password Manger 4.0 Access Gateway 4.0

Presentation Server 4.5 followed next with Application Streaming, Configuration Logging, Health Monitoring and Recovery and the newly named Access Management Console. Presentation Server 4.5 saw the introduction of Feature Pack 1 with Smart Auditing, as well as Platinum licensing etc. Once again Citrix standardised the naming of many products to 4.5 at this time.

The big name change…
As of April 11, 2008 the nomenclature of Presentation Server 4.5 courses, exams and related certifications have been updated to include the Citrix XenApp name. This name change brings Presentation Server into line with other Citrix Products such as XenServer and XenDesktop. Citrix acquired XEN Source in 2007 for $500 million. XenApp 5.0 which was released late 2008. It has many improvements and fully supported for Windows Server 2008 and most noticeably the sexy black Web Interface 5.0. Then came the true XenApp with its version Xenapp 6.0