IBM.Data.Informix exists in two versions: SQLI legacy provider and new IDS provider
https://www.ibm.com/support/knowledgecenter/en/SSGU8G_14.1.0/com.ibm.cliapinode.doc/netdif.htm
Copy provider you want to use for testing to this folder from sub-folder and switch connection string, as they differ per-protocol.
