In Asklepios Kliniken Langen-Seligenstadt GmbH & Asklepios Dienstleistungsgesellschaft mbH v Ivan Felja & Vittoria Graf (Case C-680/15 and Case C-681/15) Advocate General Bot considered once again (following the CJEU's prior decision in Alemo-Herron & others v Parkwood Leisure Ltd (Case C-426/11)) the survival of a collective bargaining clause in employees' employment contract following a transfer of an undertaking.

The Advocate General considered that when a contract of employment concluded between the transferor and the employee contains a clause referring to terms and conditions determined by a collective agreement, but neither the transferor nor the transferee may participate in the process of negotiating that agreement, the collective bargaining clause does not survive. 

So a new employer is not bound by the terms of a collective agreement entered into after the transfer where the new employer was not a party to that agreement.  This fundamental principle is now enshrined in TUPE, via Reg 4(5B). 

Opinions of Advocates General are not binding on the Court of Justice itself.  But they are usually followed.