message: Add [matrix] replacement string to be backwards compatible with $matrixLogo change
diff: @@ -56,6 +56,7 @@ export default class Welcome extends React.PureComponent<IProps> {
  "$riot:ssoUrl": "#/start_sso",
  "$riot:casUrl": "#/start_cas",
  "$matrixLogo": MATRIX_LOGO_HTML,
  + "[matrix]": MATRIX_LOGO_HTML,
  }}
  />
  <LanguageSelector />
  