Conversations is an XMPP client that connects to an XMPP server. Conversations will never upload data to the developer. The only execption to this rule is data collected after a crash. This data will be send via your own XMPP account but never without your explicit consent.
Conversations or its developers don’t have control over the data you send through the app. However the following data might get uploaded to your XMPP provider:
Using the conversations.im XMPP provider is optional. Conversations will connect to almost any other XMPP provider.