SIMPLE.ERP client is vulnerable to MS SQL protocol downgrade request from a server side, what could lead to an unencrypted communication vulnerable to data interception and modification.
This issue affect SIMPLE.ERP from 6.20 to 6.30. Only the 6.30 version received a patch 6.30@a03.9, which make it possible for an administrator to enforce encrypted communication. Versions 6.20 and 6.25 remain unpatched.
A protocol or its implementation supports interaction between multiple actors and allows those actors to negotiate which algorithm should be used as a protection mechanism such as encryption or authentication, but it does not select the strongest algorithm that is available to both parties.