code: func (tag *Tag) SetVersion(version byte) {
  	if version < 3 || version > 4 {
  		return
  	}
  	tag.version = version
  	tag.setDefaultEncodingBasedOnVersion(version)
  }
docs: // SetVersion sets given ID3v2 version to tag.
  // If version is less than 3 or greater than 4, then this method will do nothing.
  // If tag has some frames, which are deprecated or changed in given version,
  // then to your notice you can delete, change or just stay them.