Article 52 Yellow and red cards
52.01
As a rule, a player or a team official sent off from the field of play and/or its immediate surrounds, including the technical area, is automatically suspended for the next match in a UEFA club competition (i.e. UEFA Champions League, UEFA Europa League, UEFA Europa Conference League or UEFA Super Cup). In case of serious offences, the UEFA Control, Ethics and Disciplinary Body is entitled to augment this punishment, including by extending it to other competitions.
52.02
In case of repeated cautions:
before the group stage, players and team officials are suspended for the next competition match after three cautions, which did not result in a red card, as well as following any subsequent odd-numbered caution (fifth, seventh, ninth, etc.);
from the first match in the group stage, players and team officials are suspended for the next competition match after three cautions, which did not result in a red card, as well as following any subsequent odd-numbered caution (fifth, seventh, ninth, etc.).
52.03
Single yellow cards and pending suspensions are always carried forward either to the next stage of the competition or to the UEFA Europa Conference League in the current season.
52.04
Exceptionally, all yellow cards and pending yellow-card suspensions expire on completion of the play-offs. They are not carried forward to the group stage. In addition, all yellow cards expire on completion of the quarter-finals. They are not carried forward to the semi-finals.
52.05
Cautions and pending yellow-card suspensions from the UEFA Champions League, the UEFA Europa League or the UEFA Europa Conference League expire at the end of the season.
. This year, Europa League games will be be played at the Stadion an der alten Försterei. I’m not sure how many more teams this affects. 
