Apple will soon be blocking VPN and Ad-blocking apps which apply to third-party browsers on iOS. The apparent issue with these apps is the use of VPNs for Ad-blocking, which Apple will be allowing exclusively via the Safari Ad-blocker API.
Aside from enforcing web browsers to use WebKit as their rendering engine, analysts speculate that this is the next move by Apple to push people into using Safari over other available browsers on the platform. Currently, users can continue using the ad-blocking and VPN apps as normal, however apple has not given the developers the ability to update the apps. This will likely cause the apps to quickly become out of date and incompatible with any future browser app updates, as well as iOS updates themselves.