my mac mini will not update to 10.14.16?

What macOS is your Mac Mini currently running?

If it is on High Sierra 10.13 or earlier,

see > How to upgrade to macOS Mojave - Apple Support

If it is on Mojave 10.14.0 thru 10.14.5, then you can use the latest Mojave Combo Updater.

see > https://support.apple.com/kb/DL2010?locale=en_US

Hi,

Did you mean that 10.14.6 update is not available on your Mac mini Late 2014?