@GrandDragnYou got that one wrong, mate. Only ICE modes changing got banned, ERS modes are still free to switch. Perhaps if you could link us your source we could clear up the noise?
As I said, you can get a good picture of what is going on if you've got a F1 TV subscription. Clips of in-race battles with ERS changing beyond the mere press of the overtake button are quite common too but they get taken down quickly. Anyway I'll try to link one here whenever one pops in my radar.
Now if you've got a way to access the full race videos, I can point you out to some examples. From the Spanish GP:
Besides that I know that at least Racefans has an ongoing archive of the radio highlights and you can see plenty of mentions to changing strats and modes.
The ruling states that the same ICE modes are locked for quali and race sessions. They're free to change other PU parameters – ERS modes, engine braking, torque etc. – but not the engine maps.
Can you please link us to the Taffin piece you speak about? Other than that, there's plenty of discussion on the famous F1 Technical forums and even the F1 Technical Subreddit, you'll often see Scarbs on both of them. That's if you don't mind some tech heavy talk, otherwise you'll also see this being discussed on the regular Formula 1 Reddit.
Edit: Just to clarify, the F1 Technical are kind of legendary. You'll see plenty of people working all around the motorsport industry in there. The respective subreddit is also great and nicely moderated. Depending on what platform you use, you'll see that some users have special tags informing they're verified members of the industry (PU guys, aerodynamicists, gearbox guys, guys from the supply chain, etc) or from the media (as I said, Scarbs is in there). This verification is done by the moderation team.
Sorry for the double posting but I guess this warrants a space of its own. I'll just refer to a few quality posts of the F1 Technical subreddit from verified users:
From a verified F1 Performance Engineer about PU modes, ICE modes and the TD 37/20 ban:
From the same user and the same discussion, going a bit in detail about how the PU supplying side of things works. That's maybe not as common knowledge as it should, but all customer teams have at least one PU guy from the engine supplier and most if not all PU settings must be validated by them before use. The teams do not have full and unabridged access to all the PU parameters. You'll often hear about this being discussed by the F1 tech guys and personnel in interviews, podcasts and such.
Dig deep enough and you'll even find direct quotes from the TD 37 itself even though it wasn't publicly disclosed by the FIA, as usual.
