Transitional period
- March 1999 - Mozilla M3 released - the first public milestone.
- May 1999 - Netscape Communicator 4.6 released for Win/Mac/X11
- June 1999 - Mozilla M7 released, including an OS/2 version. Much of the early Mozilla porting work was done by John Fairhurst, with some contributions from Bill Law and others.
- September 1999 - IBM releases first OS/2 port of Netscape 4.61
- August 2000 - Innotek releases OS/2 version of Flash 5; this was the short-lived "golden era" of plugin compatibility, as IBM provided excellent Java support, and there was an Acrobat 3 plugin.
- October 2000 - Mozilla M18 released; including an OS/2 version. KDE 2.0 released, with Konqueror browser using KHTML.
- March 2001 - Mozilla 0.6 released, including an OS/2 version. This formed the basis of Netscape 6.0, which was largely a disaster.
- May 2001 - Mozilla 0.9, including an OS/2 version. The 0.9.x line continued with several point releases over the next few months. Henry Sobotka was one of the major OS/2 contributors during this period.
- July 2001 - last IBM refresh of the OS/2 version of Netscape 4.61
- October 2001 - IE 6.0 released; IE development subsequently abandoned for 5 years, causing web developers pain and anguish for years to come.

