Dear colleagues, We are pleased to announce the webinar on paired refinement to be held on March 23, 2021, from 3 PM (CET) to 4 PM (CET). This protocol provides an accurate estimation of the high-resolution cutoff (https://journals.iucr.org/m/issues/2020/04/00/mf5044/). The "PAIREF webinar" will be a free virtual event for up to 300 participants. The meeting will be recorded. Please register and receive your Zoom link here: https://kipl-indico.fjfi.cvut.cz/e/pairef We will cover: 1. Introduction to paired refinement. 2. Installation of PAIREF for CCP4 and/or PHENIX users. 3. Short tutorial (files will be provided). 4. Discussion. Feel free to contact us with your data. Best regards, Petr Kolenko, Martin Maly, Kay Diederichs and Jan Dohnalek