# Upgrade Guide

## Before Upgrading

1. Back up the site files and database.
2. Export BrandMail Pro settings if the plugin is already installed.
3. Confirm WordPress and PHP meet the minimum requirements.

## Legacy Source Plugin Compatibility

BrandMail Pro includes compatibility for the prior internal source plugin:

- Legacy `tsn_send_branded_email()` calls are routed to BrandMail Pro when the legacy function is not already defined.
- Legacy `tsn_send_notification_email` actions are routed to BrandMail Pro.
- Common legacy template keys and merge fields are mapped to commercial BrandMail Pro names.
- Legacy branding settings are migrated when detected during activation.

## After Upgrading

1. Review **BrandMail Pro > Branding**.
2. Review all enabled templates.
3. Send a test email.
4. Confirm privacy and retention settings.
5. Export a fresh settings backup.