Perhaps this hasn't been merged in yet. @wilsonge when was the last merge from staging to 4.0?

@franz-wohlkoenig reinstall should be on the Live Update Tab. Can you double check that?

About 8 days ago. I desperately need to find time to do an update

@zero-24:

@franz-wohlkoenig @C-Lodder it has nothing to do with a not uptodate 4.0 vs staging (that can be checked too but it should not be a problem) as the feature is included since 3.6.x it looks like the complete updater is broken in 4.0.. i have opend a issue with my findings: #14471

@zero-24 is there a way to get daily update of nightly-builds by click on Joomlaupdate without have them manually downloaded and installing?

As the updater is broken in 4.0 no. ;) in 3.7 you can use the reinstall button as it does the same ;)

Using Button Reinstall Joomla core files updates to latest nightly builds? Thanks, this Info i missed.

Yes if you set the correct update server and the url points to the nightly build. ;)

please test #14540 and please manuall apply the changes to 4.0 if you test there as the PR is against staging.