Installing .pak Files on WebSphere Application Server 8.5.x

Background

In WAS 7.0 (and possibly earlier), the WebSphere Update Installer was used to install WAS fix packs, which would have a file extension of .pak. Additionally, some other software (IBM Security Identity Manager 6, for example) that runs on WAS decided to package their updates in the same way, with .pak files to be installed with the Update Installer. WAS 8.5 moved to using IBM Installation Manager for its installation and the installation of fix packs. The last version of the WebSphere Update Installer is 7.0.0.45.

Let's say after you installed ISIM 6 on WAS 7, and then later upgraded WAS to 8.5. How do you install an ISIM 6 fixpack onto WAS 8.5?

Solution

You use the WAS 7.0.0.45 Update Installer, of course! 

WebSphere Update Installer is actually a standalone product that isn't reliant on any particular version of WebSphere to be installed. Its version number does its best to throw you off, but it works just fine when run against WAS 8.5 (or even 8.5.5.23 in my latest test).

I couldn't find this spelled out anywhere, so I thought I would share.