updating an old Mac mini

If you want to keep using it... Mostly you just need a more modern Browser than Safari on Mojave, or High Sierra like Firefox or Brave.

https://brave.com/

https://www.mozilla.org/en-US/firefox/83.0/system-requirements/

Firefox 83.0 System Requirements (mozilla.org)

Opera…Thanks

https://www.opera.com/download/requirements

Opera system requirements | Opera

Thanks to dialabrain…

Firefox 115 is now the current version. runs in High Sierra.

https://www.mozilla.org/en-US/firefox/new/

Thanks to A Brody, Browsers by Mac operating system…

Browsers by Mac operating system - Apple Community

Look into the Free LibreOffice, it handles MS Office files like Word & Excel, & Page Layout…

https://www.libreoffice.org/

Thanks to Matti Haveri…

https://discussions.apple.com/thread/254698315?answerId=258771288022#258771288022

LibreOffice 4.0.6.2_MacOS_PPC works in OS X 10.5.8 (last official PowerPC version).

LibreOffice 4.3.7.2_MacOS_x86.dmg (and x86-64?) works in OS X 10.6.

LibreOffice 7.0.4 works in macOS 10.11 and 10.14.

https://downloadarchive.documentfoundation.org/libreoffice/old/

Thanks to Servant to Cats…

LibreOffice is up to

• Version 7.5.4 – Requires Mojave or later
• Version 7.4.7 – Requires High Sierra or later
• The LibreOffice site is now offering
• Version 7.6.2 – Requires Catalina or later
• Version 7.5.7 – Requires Mojave or later

Release notes indicate that as of August 2023, new versions of LibreOffice will likely require Catalina or later.

MacTracker says a MacMini4,1 is a Mac mini (Mid 2010) or Mac mini Server (Mid 2010). For both of those, macOS 10.13.6 (High Sierra) is the end of the line.

If you download FireFox, I don't think you need to go all the way back to Firefox 83.0. While the High Safari version no longer gets new feature, I believe the one you want would be Firefox 115 ESR.

https://support.mozilla.org/en-US/kb/firefox-users-macos-1012-1013-1014-moving-to-extended-support

That model can't be upgraded past High Sierra.

(245897)

High Sierra is the latest you can run.

You're welcome.