Runtime Requirements
| Component | Development Snapshot Requirement |
|---|---|
| PHP | PHP 8.1 or later in the source; the exact deployed runtime must be pinned and validated. |
| Database | MySQL or MariaDB with InnoDB. |
| WHMCS | An isolated, licensed installation with its exact version recorded. No universal version compatibility is claimed. |
| Transport | HTTPS and a configured native WHMCS mail provider. |
| Configuration | An operator-managed private path outside the web root. |
Mail Providers
The source supports WHMCS provider adapters for PHP Mail, SMTP, SendGrid, Mailgun, SparkPost and Microsoft Graph, subject to availability in WHMCS. Having an adapter does not prove that your selected provider can deliver messages: test the configured provider end to end.
Compatibility Checks
- Use the same canonical WHMCS root and HTTPS SystemURL as the installation.
- Verify your theme, login and checkout flow using a consented test account.
- Test API, mobile and upgrade journeys separately where they are used.
- Do not run two independent email enforcement gates without a reviewed migration plan.