I'd read that as "by default we don't keep logs, so we can't be compelled to provide IPs for sessions in the past. We can still be compelled to provide that information for current/future connections."

It is in contrast to the immediately following paragraph, which discusses a user-controllable setting that does cause ip logs to be retained permanently.

What immediately following paragraph? This is what I see:

https://i.imgur.com/6sZFn78.png

In the twitter screenshot linked to in this post, there is a discussion of the authentication logging feature in the immediately following paragraph (the screenshot discussing IP logging).

https://twitter.com/OnEstLaTech/status/1434576598418796549?t...

How do you understand „by default“ and „keep“ in this phrase? Does it actually mean that they do not collect the logs?

My first reading of "by default" here is that I can optionally enable it through my account.

Really, it's a phrase that means 3 things: I can enable it, ProtonMail can enable it[0], or the authorities can compel ProtonMail to enable it.

Saying any of that, or at least linking to a page that does, would be a smart move.

[0] https://protonmail.com/privacy-policy - "IP logs may be kept temporarily to combat abuse and fraud, and your IP address may be retained permanently if you are engaged in activities that breach our terms and conditions"