My ATV 2 shows software version 5.3 (6105); Is this the most current version?

I was previously "stuck" on Ver 5.2.1, with "update software" reporting that it was current, and only after restoring by conneting to iTunes via USB was I able to update to 5.3, so I'm wondering what the current software version is, so I can know if it is really up-to-date, or just "stuck" like it was before.