Yes, Probate Plus can operate under terminal service environments such as those provided by Citrix and there is no "specific" version of Probate Plus for terminal server / multiplexing environments.
Your IT department would need to install Probate Plus into their application server environment in the same way that they would deploy any application such as MS-Word or MS-Excel.
IMPORTANT - One caveat is that you will need an Advantage Database Server licence to match the number of concurrent users that will be operating Probate Plus under the terminal server environment. This is because Citrix / Terminal Services acts as middleware. It effectively provides similar performance and features as when using the Advantage Database Server to provide client-server functionality and this middleware breaches the ADS licence terms if used without an ADS "server" licence.
A warning error "Advantage 5185" is triggered by the database engine that Probate Plus uses when a terminal services environment is detected. Advantage Database Server licences come in a variety of sizes from 2-250 users and are available from Law Systems Limited or direct from any number of online retailers.