I reinstalled 3 times already, deactivated automatic updates. Version 220.127.116.11 gets installed, has old design and working eq. After second start (or at second usage) I have the new design with malfunctioning equalizer.
Phone is iPhone 6 with latest official iOS version, no jailbreak or other special configuration.
Another thing...you say Spotify is always testing new things. I work in the software industry, at a very detailed level. If I were to "test" something on a working environment, i would no longer be working in the software field. Furthermore, how do I get removed from the "test" group?
I had the new view all of a sudden too and I liked it much. It's hard to push the buttons on the left corner on an iPhone 6S plus. But the equalizer didn't open too, even if I reinstalled it.
At same time I opened Spotify on my iPhone 6 and had the old view. After I restarted it a few times I had the new view too. On my 6S+ it changed from new to old simultaneously. After I updated Spotify yesterday I only have the old view (I don't like it) I want the buttons on the button again.