NOTE: There is a special tool to run macOS Catalina on your Unsupported Mac:

Early-2008 or newer Mac Pro, - iMac, or - MacBook Pro:
- MacPro3,1
- MacPro4,1
- MacPro5,1
- iMac8,1
- iMac9,1
- iMac10,x
- iMac11,x (systems with AMD Radeon HD 5xxx and 6xxx series GPUs will be almost unusable when running Catalina.)
- iMac12,x (systems with AMD Radeon HD 5xxx and 6xxx series GPUs will be almost unusable when running Catalina.)
- MacBookPro4,1
- MacBookPro5,x
- MacBookPro6,x
- MacBookPro7,x
- MacBookPro8,x

Late-2008 or newer - MacBook Air or Aluminum Unibody - MacBook:
- MacBookAir2,1
- MacBookAir3,x
- MacBookAir4,x
- MacBook5,1

Early-2009 or newer Mac Mini or white - MacBook:
- Macmini3,1
- Macmini4,1
- Macmini5,x (systems with AMD Radeon HD 6xxx series GPUs will be almost unusable when running Catalina.)
- MacBook5,2
- MacBook6,1
- MacBook7,1

Early-2008 or newer Xserve:
- Xserve2,1
- Xserve3,1

All the latest Mac systems are good also.

macOS Catalina gives you more of everything you love about Mac. Experience three all-new media apps: Apple Music, Apple TV, and Apple Podcasts. Locate a missing Mac with the new Find My app. And now coming to Mac, your favorite iPad apps. You can even extend your desktop using iPad as a second display. Now you can take everything you do above and beyond.

https://apple.com