_zimfw_upgrade() {
  local -r zscript=${ZIM_HOME}/<%= script_filename %>
  local -r zurl=https://raw.githubusercontent.com/zimfw/zimfw/develop/<%= script_filename %>
  {
    if (( ${+commands[wget]} )); then
      command wget -nv ${1} -O ${zscript}.new ${zurl} || return 1
    else
      command curl -fsSL -o ${zscript}.new ${zurl} || return 1
    fi
    if command cmp -s ${zscript}{,.new}; then
      if (( ! _zquiet )); then
        print -P '<%= okay %>%B<%= script_filename %>:%b Already up to date'
      fi
    else
      command mv -f ${zscript}{,.old} && command mv -f ${zscript}{.new,} && \
          if (( ! _zquiet )); then
            print -P '<%= okay %>%B<%= script_filename %>:%b Upgraded. Restart your terminal for changes to take effect.'
          fi
    fi
    if (( ! _zquiet )); then
      print -P '<%= done %>Done with upgrade.'
    fi
  } always {
    command rm -f ${zscript}.new
  }
}