This upgrade makes no changes to the cdrs, so "enswitch upgrade" should run quickly even on large systems.

Before upgrading

1. Review the functional changes, and ensure that none will cause problems.
2. If running MySQL 8.x, check that its server configuration files do not include the "STRICT_TRANS_TABLES" value for the "sql_mode" option, because it will cause runtime failures in some Enswitch functionalities.
3. If the database or some of its tables use the "latin1" character set, change it to "utf8mb4".

To upgrade

1. On all machines, check out /opt/enswitch/4.3.
2. On all machines, update the /opt/enswitch/current symlink.
3. On all web machines running Debian or Ubuntu:
   • apt install libatk-bridge2.0-0 libxkbcommon-x11-0 libxcomposite1 libxdamage1 libjson-webtoken-perl libxrandr2 libgtk-3-0 libgbm1
   • curl -sL https://deb.nodesource.com/setup_12.x -o /tmp/nodesource_setup.sh
   • bash /tmp/nodesource_setup.sh
4. On all web machines running CentOS, Redhat Enterprise, or Fedora:
   • yum install atk at-spi2-atk gtk3 libdrm libXcomposite libXdamage mesa-libgbm
   • cpanm JSON::WebToken
   • curl -sL https://rpm.nodesource.com/setup_12.x -o /tmp/nodesource_setup.sh
   • bash /tmp/nodesource_setup.sh
5. On the primary web machine:
   • cp /opt/enswitch/current/install/etc/crontabs/web /etc/cron.d/enswitch_web
6. On the primary database machine:
   • enswitch upgrade
7. On all machines:
   • enswitch restart
8. Test calls and the web interface.
9. On the primary database machine:
   • enswitch after_upgrade