The MaxHistory does not do the trick : the old files are not deleted at all :
cat logging.xml
<appender name="IDP_ACCESS" class="ch.qos.logback.core.rolling.RollingFileAppender">
<File>/shibboleth-idp/logs/idp-access.log</File>
<Append>false</Append>
<ImmediateFlush>true</ImmediateFlush>

<RollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<FileNamePattern>/shibboleth-idp/logs/old/idp-access-%d

.log.gz</FileNamePattern>
<MaxHistory>3</MaxHistory>
</RollingPolicy>

<layout class="ch.qos.logback.classic.PatternLayout">
<Pattern>%msg%n</Pattern>
</layout>
</appender>