According to the board in T 166/84 (OJ 1984, 489), where a decision of the examining division depends entirely on the outcome of proceedings before the Enlarged Board of Appeal on a legal question raised under Art. 112 EPC 1973 ‑ and this was known to the examining division ‑ the further examination of the application must be suspended until the matter is decided by the Enlarged Board of Appeal. Failure to do so amounts to a substantial procedural violation under R. 67 EPC 1973 (R. 103(1)(a) EPC).
According to the Guidelines for Examination (E‑VI, 3 – November 2015 version), where the outcome of examination or opposition proceedings depends entirely on the answer to questions referred to the Enlarged Board, the proceedings may be stayed by the examining or opposition division on its own initiative or on request of a party. Under a previous version of the guidelines (E‑VI, 3 – September 2013 version), the proceedings were to be stayed "only upon request of at least one of the parties" (see also Notice from the EPO dated 1 September 2006 concerning staying of proceedings, OJ 2006, 538).
When G 3/14 (concerning clarity objections in opposition proceedings) was pending before the Enlarged Board, the President of the EPO decided that all proceedings before the opposition divisions where the decision depended entirely on the outcome of the Enlarged Board's decision were to be stayed ex officio, thereby superseding the then general practice under the guidelines to stay proceedings only upon request of a party (Notice from the EPO dated 7 August 2014 concerning the staying of proceedings due to referral G 3/14, OJ 2014, A87, see also Notice from the EPO dated 2 October 2015 concerning the staying of proceedings due to referral G 1/15).