Jicofo startup error at org.jitsi.jicofo.Main.main: Parameter [secret] not found

after updating a perfectly running installation of Jitsi Meet, I get the following start-up error in jicofo.log:

Jicofo 2020-07-26 13:32:27.921 SEVERE: [1] org.jitsi.jicofo.Main.log() An uncaught exception occurred in thread=Thread[main,5,main]
org.jitsi.cmd.ParseException: Some of required arguments were not specified: [secret]
at org.jitsi.cmd.CmdLine.parse(CmdLine.java:130)
at org.jitsi.jicofo.Main.main(Main.java:138)

File /etc/jitsi/jicofo/config is readable and should contain the missing parameter (“JICOFO_SECRET” as I understand):

#sets the XMPP domain (default: none)
#sets the secret used to authenticate as an XMPP component
#sets the port to use for the XMPP component connection
#sets the XMPP domain name to use for XMPP user logins
#sets the username to use for XMPP user logins
#sets the password to use for XMPP user logins
#extra options to pass to the jicofo daemon
#adds java system props that are passed to jicofo (default are for home and logging config file)
JAVA_SYS_PROPS="-Dnet.java.sip.communicator.SC_HOME_DIR_LOCATION=/etc/jitsi -Dnet.java.sip.communicator.SC_HOME_DIR_NAME=jicofo -Dnet.java.sip.communicator.SC_LOG_DIR_LOCATION=/var/log/jitsi -Djava.util.logging.config.file=/etc/jitsi/jicofo/logging.properties"

I checked for 2 days all possible sources of errors (including strange hidden codes in config file), to no avail.
I also tried to switch to a higher log level in jicofo/logging.properties by setting .level=FINEST, but still get only this one message in the log, nothing else.
What can be missing or wrong? From the jicofo:main source, I see there might be an env variable “SECRET_ARG_NAME” involved?
How can I activate TRACE log level in Jicofo?

Thanks in advance for your help,

Problem solved by reinstalling the files in /usr/share/jicofo from backup. Reason was probably some broken file(s) during update.