stable
curl https://upgrade.mikrotik.com/routeros/LATEST.6
long term
curl https://upgrade.mikrotik.com/routeros/LATEST.6fix
testing
curl https://upgrade.mikrotik.com/routeros/LATEST.6rc
development
curl https://upgrade.mikrotik.com/routeros/LATEST.7
輸出有兩個欄位
6.44.3 1556023023
第一個欄位是版本, 第二個欄位應該是 build time (seconds since 1970-01-01 00:00:00 UTC)
目前 development 無資料 (404 Not Found)
