That's our mistake, forgot to add an version mismatch alert 
I'm really sorry for this, we will certainly improve it in next update.
It's a long story, the earlier versions of Core Tunnel actually distributed outside of Mac App Store, you can find the discussion from this thread:
TL;DR, Apple rejects apps that access system resources, the functionality is restricted if we didn't introduce Core Helper. But since Core Helper access system resources (on behalf of Core Tunnel), it has no chance to land on Mac App Store (which is forbidden by Apple).
Distribute Core Helper outside of Mac App Store is a compromise that is acceptable to both Apple and users.