Much of the software installed on the NeSI cluster have multiple versions available as shown here or by using the module avail or module spider commands.
If only the application name is given a default version will be chosen, generally the most recent one. However it is good practice to load modules using the specific version so you can ensure consistent execution of your job even after the default version has been changed.
If you need a specific version of software, feel free to ask support and we may install it.
Example
module load ANSYSWill load the default version of ANSYS, in this case ANSYS/19.2, however this may change.
module load ANSYS/18.1Will always load that version specifically.