I haven't noticed a drop in performance myself, but I have read that there is a problem with some people on Twitter. One way I've seen suggested to combat this is to turn off 'Background App Refresh' in the general settings. Not sure how much use that would be but it could be worth trying.
I think my main A/V receiver is on its way out. I can replace it fairly easily, but what if it doesn't sound exactly the same? This amp + these EQ settings + these headphones = The world's best audio. No questions asked. And no, I can't replace like for like. This amp is from 1991. Bought by my dad and I believe the first album it played was the freshly released Achtung Baby.