Shift+Enter newline on Messages (Karabiner Elements 12)

messages_newline.json

{
  "title": "Shift+Enter newline on Messages",
  "rules": [
    {
      "description":"Change Shift+Enter to Ctrl+Enter in Messages",
      "manipulators":[
        {
          "type":"basic",
          "from":{
            "key_code": "return_or_enter",
            "modifiers": {
              "mandatory": [
                "shift"
              ]
            }
          },
          "to": [
            {
              "key_code": "return_or_enter",
              "modifiers": [
                "control"
              ]
            }
          ],
          "conditions": [
            {
              "type": "frontmost_application_if",
              "bundle_identifiers": [
                "^com.apple.iChat"
              ]
            }
          ]
        }
      ]
    }
  ]
}

https://medium.com/@ryan.willis/how-to-use-shift-enter-to-insert-a-new-line-in-messages-on-macos-1704fb5b3254

Great article. Thank you!