Perhaps I should be happy at not having to deal with OS updates, but it seems odd to me that I've never received any OS updates for my Kindle Fire (original), purchased June 2012.

a) Is 6.3.1 current?

b) The actual full version number shown in Settings, Device is 6.3.1_user_ and then seven digits. What's with that? I'm reluctant to post the actual seven digits for fear it might be some kind of personal identifying information, but the first three of the seven digits are 410.

c) "Update Your Kindle" button is greyed out.

d) There are many minor issues with the current OS, notably clumsiness in responding to touch (I make more typos on the Kindle keyboard in Landscape mode, 7" wide, then I do on my iPod Touch in Portrait mode, 2" wide. An unexpected disappointment.). Reputedly this is a known issue with older versions of Android that's been greatly improved in Key Lime Pie. Has anyone heard whether Amazon intends to make further updates available, or is 6.3.1 the end of the line?