Greetings to the TinyCore Team,
actually I did not find a TinyCore/CorePlus iso-image with Version 4.7.4 in the filename.
Instead I found core.gz and vmlinuz under 'Release Candidates'.
I have a pendrive, bootably prepared with Version 4.7.3 and some extensions and data.
Within its Boot/ directory I first deleted the old core.gz
Then I added the downloaded core.gz
and also replaced vmlinuz in the same two-step way.
Then I checked it on a laptop: it works fine.
This is a fast way to also update the core of a pendrive installation, if the AppBrowser indicates a newer core version, no need to repeat the whole installation procedure every times.
Great thanks for this tiny system!