For this matter Lightstreamer entirely delegates to logback and leans on its features.
Our suggestion it to set a filter on the appender that manages your log file, rather than reconfiguring all loggers, so that you can switch to a more verbose log easily when needed.

This means adding inside the appender definition the following:
<filter class="ch.qos.logback.classic.filter.ThresholdFilt er">
<level>error</level>
</filter>
(if you copy that, please be aware that the formatting may introduce spurious spaces).

You can also see an example in the factory log configuration file.
At the beginning of the definition of the LSDailyRolling appender, you can see a filter commented out.