Can I go from OS High Sierra to OS Catalina
Can I safely upgrade to OS Catalina from OS High Sierra?
MacBook Pro 15″, macOS 10.13
Yes if you quailfy
see 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
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https://www.apple.com/macos/catalina/
https://itunes.apple.com/us/app/macos-catalina/id1466841314?mt=12&l=en-us
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 High Sierra 10.13 ... - Apple Support