RK-CMS and RichExchanger are not the same thing.
RK-CMS is a self-sufficient and independent content management system with advanced financial features.
RichExchanger is an add-on to RK-CMS for building an e-currency exchange website.
The RichExchanger project has been shut down.
We won't go into the reasons; it just happened and is irreversible.
Despite the fact that the RichExchanger code is no longer shared or distributed, some people are trying to distribute it or even sell it.
This is a blatant scam, as a closed project has no support, no development, and no future.
RichExchanger ran on RK-CMS version 5.3. Any recent version of RK-CMS is not supported.
Attempting to update RichExchanger to a more recent, secure version will result in the site and extension simply ceasing to function. In the worst case, numerous errors will appear.