_zimfw_check_version() {
  if (( ${1} )); then
    # Get latest version (get all `v*` tags from repo, delete `*v` from beginning,
    # sort in descending `O`rder `n`umerically, and get the `[1]` first)
    if (( ${2} )); then
      # background check
      if [[ -w ${_zversion_target:h} ]]; then
        print -R ${${(On)${(f)"$(GIT_HTTP_LOW_SPEED_LIMIT=1000 GIT_HTTP_LOW_SPEED_TIME=30 command git ls-remote --tags --refs \
            https://github.com/zimfw/zimfw.git 'v*' 2>/dev/null)"}##*v}[1]} >! ${_zversion_target} &!
      fi
    else
      # foreground check
      local tags
      tags=$(command git ls-remote --tags --refs https://github.com/zimfw/zimfw.git 'v*') || return 1
      >! ${_zversion_target} <<<${${(On)${(f)tags}##*v}[1]} || return 1
    fi
  fi
  if [[ -f ${_zversion_target} ]]; then
    local -r zlatest_version=$(<${_zversion_target})
    if [[ -n ${zlatest_version} && ${_zversion} != ${zlatest_version} ]]; then
      _zimfw_print -u2 -PR "%F{yellow}Latest zimfw version is %B${zlatest_version}%b. You're using version %B${_zversion}%b. Run %Bzimfw upgrade%b to upgrade.%f"
      return 4
    fi
  fi
}