The arguments useSsl, trustServerCertificate and disableSslHostnameVerification have been deprecated, and now there is a compatibility work around to map them to the new sslMode argument.

The issue is that the method isSet(String, Properties) in Configuration.java that is used for that compatibility is case sensitive, while the 2.x driver was not. All other arguments don't seem to be case sensitive, dealing with it either by using parseBoolean or converting the property value to lower case before checking.