You can look at the Readme to determine the version of the SCL that is available. The Readme is located at:
http://publib.boulder.ibm.com/epubs/df/ebrsclwj.txt
The first line of the Readme contains the version number.
Your installed level is displayed in the system Start menu. Click on Start->Programs->IBM SoftCopy Librarian V4. The next list contains SoftCopy Librarian Vn.nn. If Vn.nn is less than the level contained in the Readme on the web, you should download and install the new version.
The latest version of the SCL can be downloaded via:
http://publib.boulder.ibm.com/epubs/df/ebrsclwj.exe
Even though the date may be older, this version is probably more recent than the version that is on the CD-ROM collections in the IBM Online Library.