If you want to try out a new update to the compiler before you remove the existing version from the system, you must install the new update to a non-default location.
To install a PTF to a non-default location, use the procedure described in Installing XL C/C++ to a location separate from earlier versions (for advanced users).
After you have finished testing the new PTF and have verified that you want to replace the older version with the new update, you can install the PTF to the default location by doing the following: