Swiss International Air Lines has made this announcement:

From October 16, 2019 onwards, Swiss will be offering a new service to the Slovenian capital of Ljubljana, departing from its hub at Zurich Airport. There will be five connections a week initially, with a daily flight from October 27, 2019.

The new route will initially be operated by Helvetic Airways. With the rollout of the winter schedule on October 27, 2019 Swiss will fly to the new destination once a day from Zurich on an alternate basis with its wet lease partner, Helvetic Airways.

Prior to discontinuation of flight operations by Adria Airways, Swiss passengers were able to travel to from Zurich to Ljubljana thanks to a codeshare agreement.
The new flights will ensure a continuing connection.