I have one player that has the 19.21, and one with 18.21 or something like that. I think unless you have problems where you need to send it in we all should be fine. Maybe some support guru's can speak on that.
I believe 19.21 is the most current release. True there is no reason to need an upgrade, unless you are having problems. They do not add any new features or anything by upgrading firmware. Actually to be quite honest, as a user I have noticed no differences in the firmwares.
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