_zimfw_upgrade() {
  local -r ztarget=${ZIM_HOME}/zimfw.zsh
  local -r zurl=https://raw.githubusercontent.com/zimfw/zimfw/master/zimfw.zsh
  {
    if (( ${+commands[wget]} )); then
      command wget -nv -O ${ztarget}.new ${zurl} || return 1
    else
      command curl -fsSL -o ${ztarget}.new ${zurl} || return 1
    fi
    _zimfw_mv ${ztarget}{.new,} && _zimfw_print -P '<%= done %>Done with upgrade.'
  } always {
    command rm -f ${ztarget}.new
  }
}