Checking the testlink information, it seems that it should take care of preforming that upgrade
if that's not the case, I suggest you ask to the developers or check the documentation to know how to proceed
No, that's not true. We configure the password of the root user of the database using the same default password we use to configure the application. So if you used the installer, the password you set in the wizard when installing the stack is the one you need to use when connecting to the database.
Please note that you need to load the Bitnami environment first and then run the command to create the backup