I’ve decided to go with enhancing the messaging system of StuDocu. It has several reasons.
Survey shows that 95% of participants are involved in a messaging groups. 39% are involved more than 5 groups. This displays a huge opportunity to consider services like WhatsApp and Telegram as competitors and try to gather some market share in this rather specific student related domain.

Survey also shows that community messaging beats cloud drive. 42% of participants are not involved even just one lecture related cloud service. But there are opportunities to merge the systems and become a definitive system for organizing, managing and sharing lecture content among students.
For the business goals of StuDocu, a stellar community messaging system will generate more content. The content uploaded here is an opportunity to feed main content pool of StuDocu.
It seems that the current implementation of messaging system is underutilized by our users. Yet this also means we have already existing investment to messaging system. We are not at ground zero.
A community system is a fit for our users already existing patterns (WhatsApp, Telegram, Discord etc) so the switching cost can be quite low. They use these product everyday, switching to StuDocu messaging system should be frictionless.