Thankfully, you can still re-enable the old version of Notepad by opening the Settings App (press Windows+i) and navigating to Apps > Advanced App Settings > App Execution Aliases ...

To make Notepad files always open in a new or separate window in Windows 11, open Notepad setting and change the 'Opening files' option.

Microsoft has added bold, italic, and Markdown support to Notepad for Windows 11, updating the famously simple text editor with formatting tools.