On launching minecraft, for the first time in a while, the launcher window shows a popup "Launcher Update: A new version of the Launcher is available. Please click here for more details."

Clicking there attempts to trigger the opening of a browser window to the URL "https://aka.ms/MinecraftLauncher", but that seems to be a broken link that now redirects to "https://www.bing.com/?ref=aka&shorturl=MinecraftLauncher".

I can't tell if there's some other way to get the launcher updated, googling didn't throw up any obvious route to do so.