Most changes in Enswitch 4.0 purely add functionality, but some change or remove functionality. Here is a list of such changes. If any of these adversely affect you, please contact support as soon as possible.

• The menu structure of the web interface has changed, with a new set of top-level menus. If you've created any custom menus, you should review their location after the upgrade and move them to the appropriate top-level menu.
• The old web interface has been removed.
• Kamailio 3.X and 4.X are no longer supported.
• Internal calls are now charged for recordings, where a recording price has been set. This behavior can be turned off with configuration setting "Charge for internal recordings".
• Custom versions of the web interface are only loaded when set with "templates = <path>" in /etc/enswitch/domains.ini.
• Credit card verification numbers are no longer stored by default.
• Credit card, bank account, PayPal, and Google Checkout details are hidden in the audit log and trace files.
• As usual, some JSON API functions have changed. If using the JSON API, these should be reviewed before upgrading.