If you just use it in the browser, <svg> is all you need. The browser is smart enough to parse it as SVG based on the context (e.g. if it's embedded inside HTML

If you just use it in the browser, <svg> is all you need. The browser is smart enough to parse it as SVG based on the context (e.g. if it's embedded inside HTML, if it's linked from an <img>, or if it's served as Content-Type: image/svg+xml). And you can omit the version.