A7
2018.09.20 

Cloudflare launched today a new service named the "Cloudflare Onion Service" that can distinguish between bots and legitimate Tor traffic.

The main advantage of this new service is that Tor users will see far less, or even no CAPTCHAs when accessing a Cloudflare-protected website via the Tor Browser.
The new Cloudflare Onion Service needed the Tor team to make "a small tweak in the Tor binary," hence it will only work with recent versions of the Tro Browser --the Tor Browser 8.0 and the new Tor Browser for Android, both launched earlier this month.
https://blog.cloudflare.com/cloudflare-onion-service/