Install CL compiler support for a previous release

You can install the *PRV CL compiler support and QSYSVxRxMx libraries.

Do the following:

To view the Licensed Program Menu, Enter the following:
```
GO LICPGM
```
Select option 11 (Install licensed programs).
Select the option that is named *PRV CL Compiler Support. This causes the QSYSVxRxMx libraries to install.
If you are not using the CL compiler support for a previous release, you can remove this support by entering the following:
```
DLTLICPGM LICPGM(5769SS1) OPTION(9)
 
```
When the CL compiler support is removed, the QSYSVxRxMx libraries get removed from the system, but the QUSRVxRxMx libraries do not. If no need exists for the QUSRVxRxMx libraries, you must explicitly delete them using the Delete Library (DLTLIB) command.

Parent topic: Compile source programs for a previous release