I think the main issue is that the properties port and ssl were allowed in v1.1, but are now ignored. I actually don't see anywhere that we document port and ssl. Did you find those in the Knex.js documentation, or did you just notice that they worked?
To specify the port, I think you can include that in the host property.
We don't have a good way right now to specify named parameters, including ssl=true. If you must specify ssl=true, you could try shoving it into the database name, since that comes last in the connection string: "database": "mydb?ssl=true". However, I'm not sure I recommend that, because the database property is intended for the database name, and this approach might not be supported in a future version.
I can't tell whether there's an issue with your password. Central v1.2 does not currently encode the password for the connection string, so there can be an issue if your password contains a symbol with special meaning. In that case, you should either change your password to something without the symbol, or percent-encode the symbol.
For more background on all this, check out the documentation on Postgres connection URIs: https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNSTRING
I'll also file a GitHub issue so that we can think more about encoding the password and specifying named parameters.