Earlier quoted context omitted.
Don’t retain the IP address, retain a hash of the IP address.
Not private enough as the space of IP addresses is too small. Removing the last octet of IPv4 addresses before storing them should provide better privacy.
That doesn't provide any practical amount of privacy. For a longer discussion of why this is at best a placebo, see: https://news.ycombinator.com/item?id=17170468