How to install a ''HOT FIX''

I want to work with the ''MODICOM MC-80'' and I have unity pro xl v11.0 but when I create a new project this PLC does not appear in the different options the program gives me.

In the data sheet of the 'MODICOM MC-80' it says the following:

1 Install Unity V8.1

2 Install the Hot fix: UnityPro_V81_HF_MC80

3 Create a new project with MC80.

I assume that for the version of unity I have should be somthing similar but I don't know how intall or even find a HOT FIX.

Thank you very much in advance.