Block withheld/hidden phone number

I can not find how to block hidden phone number calls (numéro masqué in french) on my /e/OS Oreo phone.
I see that I can build a list of rejected phone numbers but how can I block calls from “unknown” ?

Thanks in advance

Regain your privacy! Adopt /e/ the unGoogled mobile OS and online servicesphone

You need a so called call blocker app for that. Good call blockers allow you to set filter options for which call should ring and which shouldn’t. Yet Another Call Blocker is good, currently I use NoPhoneSpam. The problem is: you probably can’t block a specific hidden phone number. When you block hidden numbers you block all at once. (But that’s normally not a loss …)

NoPhoneSpam looks good. It’s just enough to block calls with hidden numbers. Might be supported natively in future /e/OS version hopefully.