code: @Nullable
    public static EHttpVersion getHttpVersion (@Nonnull final HttpServletRequest aHttpRequest)
    {
      ValueEnforcer.notNull (aHttpRequest, "HttpRequest");
  
      final String sProtocol = aHttpRequest.getProtocol ();
      return EHttpVersion.getFromNameOrNull (sProtocol);
    }
docs: Get the HTTP version associated with the given HTTP request
  
  @param aHttpRequest
  The http request to query. May not be <code>null</code>.
  @return <code>null</code> if no supported HTTP version is contained