Gadgetbridge/app/src/main/assets/logback.xml

<configuration debug="true">

    <appender name="STDOUT" class="ch.qos.logback.classic.android.LogcatAppender">
        <!-- encoders are  by default assigned the type
             ch.qos.logback.classic.encoder.PatternLayoutEncoder -->
        <encoder>
            <pattern>%msg</pattern>
        </encoder>
    </appender>

    <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <file>${GB_LOGFILES_DIR}/gadgetbridge.log</file>

        <lazy>true</lazy>
        <!-- encoders are  by default assigned the type
             ch.qos.logback.classic.encoder.PatternLayoutEncoder -->
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <fileNamePattern>${GB_LOGFILES_DIR}/gadgetbridge-%d{yyyy-MM-dd}.%i.log.zip</fileNamePattern>
            <maxHistory>10</maxHistory>
            <timeBasedFileNamingAndTriggeringPolicy
                class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                <!-- or whenever the file size reaches 50MB -->
                <maxFileSize>2MB</maxFileSize>
            </timeBasedFileNamingAndTriggeringPolicy>
        </rollingPolicy>
        <encoder>
            <!--<pattern>%date %level [%thread] %logger{10} [%file:%line] %msg%n</pattern>-->
            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{1} - %msg%n</pattern>
            <!-- to debug crashes, set immediateFlush to true, otherwise keep it false to improve throughput -->
            <immediateFlush>false</immediateFlush>
            <!--<pattern>%date [%thread] %-5level %logger{25} - %msg%n</pattern>-->
        </encoder>
    </appender>

    <root level="DEBUG">
        <appender-ref ref="STDOUT" />
        <appender-ref ref="FILE" />
    </root>
</configuration>