The earlier versions of UiPath supported the automation of Virtual Environments only through Image & Text Automation. The option of Citrix Recording was being used for the same. You can see that from the screenshot of options under Citrix Recording below.
From v2018.4 onward, its is possible to automate Citrix Apps just like any other applications. Native Citrix Recording option allows to identify UI elements in Citrix Apps and automate them. This is clear from the options available under Native Citrix Recording.
On the other hand, Image Recording still exists to perform traditional Image & Text Automation.
Hope this helps,