This may sound rather odd, even quaint, but I have never - to the best of my knowledge ! - updated any of my Sony stable, (including the ones "lifted" from my ownership by my offspring)..........
I'm now using Win 8 (I presume the first version) - and, incidentally, loath it with all my being - and have never had any problems ..........................
Admittedly, I have only ever, apart from my first couple of books, used Calibre and the services of Apprentice Alf, and continue to do so .....
( Umm... and I don't use the public library facility. although yes, I know I should ....)
But here's the thing ..... should I go for a last burst of Sony "improvements" with my PRS'SSSS & T'S before it's too late, just in case I need to be "future-proofed" in some way, or should I (and sprog) simply leave well alone ?