You will be able to update TSplus as long as your subscription to Support and Update is active.
Updates are available from the Home tab of the admin tool by clicking on the version button as shown below :
Make sure no users are logged in before installing this update, you can check for remote users by launching a task manager and clicking on the users tab.
Disabling your antivirus is also recommended.
Make a scan exclusion rule on C:\wsession and C:\Program Files (x86)\TSplus\UserDesktop\files and make sure your users have sufficient rights to read and execute all programs in these folders.
A reboot will be required. You will find more detailed information about TSplus updating process here : https://www.terminalserviceplus.com/docs/updating-terminal-service-plus