Following the instruction I stop the service using the command:
sudo service WowzaStreamingEngineManager start
Then I use the command:
sudo ./update.sh
The reply is always the following:
Verifying running as administrative user Locating Wowza Streaming Engine installation directory
Locating Wowza Streaming Engine installation directory
Wowza Streaming Engine appears to be running. Please stop it before continuing.
Unfortunately, the text I wrote in my question is not correct. I did
sudo service WowzaStreamingEngineManager stop
sudo ./update.sh
and the answer was
Verifying running as administrative user Locating Wowza Streaming Engine installation directory Locating Wowza Streaming Engine installation directory Wowza Streaming Engine appears to be running. Please stop it before continuing.
I can add that If I use the Wowza Manager Web Interface does not work after the command
sudo service WowzaStreamingEngineManager stop
and, of course, the web interface is ok is I do the command