OS/2 Warp 4 incorporated a number of new technologies over OS/2 Warp 3, such as Java, OpenGL, OpenDoc, and VoiceType. It also updated the appearance of the Workplace Shell.
4.52 was the last release from IBM. Later versions of this OS are available from Serenity Systems under the name eComstation.
These are full install media that basically include all Warp 4 fixes at the time of release. IBM referred to these CDs as "OS/2 Convenience Pack"
Note on build numbers:
There are some additional language versions here: https://archive.org/download/OS2Warp4.52 but they seem to suffer from file corruption.