Type, class, instrument ratings - Can the refresher assessment be theoretical or is it in-flight?

In accordance with the EASA Resolution dated 18.03.2020, in the case of availing of this Resolution, the assessment to be carried out shall be as determined by the Operator in accordance with the exemption that may apply to his Authority.
For the cases covered by the EASA Resolution dated 05.05.2020 and in the case of availing of this Resolution, the briefing shall be conducted as determined by the instructor.