SOFTWARE QUESTION

Catalina was updated four weeks ago to 10.15.5.

https://support.apple.com/kb/DL2039?viewlocale=en_US&locale=en_US

and a supplemental update was released within a couple of days,

https://support.apple.com/kb/DL2043?viewlocale=en_US&locale=en_US

Probably in September or October Catalina will be replaced with 10.16.

Typically you are always better off running the most current macOS your machine will allow—especially for the built in security features.

Old app compatibility maybe one reason to hold back— you have to do your own homework here: https://roaringapps.com/apps

32-bit app compatibility with macOS ... - Apple Support

https://support.apple.com/en-us/HT208436

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https://www.apple.com/macos/catalina/

https://itunes.apple.com/us/app/macos-catalina/id1466841314?mt=12&l=en-us

macOS Catalina - Technical Specifications - Apple Support

https://support.apple.com/kb/SP803?locale=en_US

System requirements macOS 10.15 Catalina

macOS Catalina will run on all Macintosh computers that supported Mojave:

MacBook: Early 2015 or newer

MacBook Air: Mid 2012 or newer

MacBook Pro: Mid 2012 or newer

Mac Mini: Late 2012 or newer

iMac: Late 2012 or newer

iMac Pro

Mac Pro: Late 2013 or newer; Mid 2010 or Mid 2012 if upgraded with a recommended Metal-capable GPU

If you are already running macOS catalina, the latest is update is 10.15.5

Combo update macOS 10.15.5 https://support.apple.com/kb/DL2040?locale=en_US

macOS Catalina 10.15.6 has not been released yet