Windows 98 build 2120

Windows 98 build 2120 is a beta build of Windows 98 Service Pack 1. This build was first shown in a BetaArchive topic by DiskingRound on 2015-12-23. It was later leaked on 2016-01-24.

Installation
The self-extracting archive  starts the update installer   with -q and -z arguments, which means silent install, no automatic restart. Just wait a while for disk activity to stop, then restart the machine to finish the installation.

Alternatively, you can unpack the archive and run  yourself to get the usual installer UI.