The major thing Windows 11 needs are Directx 12 Video Card. 9 Inch or larger 720P(1280 x 720) or better monitor. Home requires Microsoft Account. Video card Something Like  MSI GT730 N730-2GD3V3  [URL] Dell 19" E198WFPV DVI 720p Widescreen LCD Monitor or better [URL] The Most glaring issue is UEFI secure boot requirement. So optiplex 9020 tower would be bare minimum update. [URL]   Processor: 1 gigahertz (GHz) or faster with 2 or more cores on a compatible 64-bit processor or System on a Chip (SoC) RAM: 4 gigabyte (GB) Storage: 64 GB or larger storage device System firmware: UEFI, Secure Boot capable TPM: Trusted Platform Module (TPM) version 2.0 Graphics card: Compatible with DirectX 12 or later with WDDM 2.0 driver Display: High definition (720p) display that is greater than 9-inches diagonally, 8 bits per color channel Internet connection and Microsoft accounts: Windows 11 Home edition requires internet connectivity and a Microsoft account to complete device setup on first use. Switching a device out of Windows 11 Home in S mode also requires internet connectivity. For all Windows 11 editions, internet access is required to perform updates and to download and take advantage of some features. A Microsoft account is required for some features.    
Just ran the check to see if Windows 11 will run on my PC and it says that it will not.  So what happens after 2025 when windows stops supporting windows 10.
windows 11 - Desktop XPS 8300