UTOPAY payment gateway for WHMCS 7.10 – 8.x (PHP 7.2 – 8.3)
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Cards, Apple Pay, Google Pay, PayPal, Revolut (4.5%) and crypto — USDT / USDC / ETH (1.5%).
Full guide: https://utopay.app/plugins/whmcs

INSTALL
1. Upload the CONTENTS of this folder to the WHMCS root (the "modules" folder merges with yours):
     modules/gateways/utopay.php
     modules/gateways/utopay/            (pay.php + lib)
     modules/gateways/callback/utopay.php
2. WHMCS admin → System Settings → Payment Gateways → All Payment Gateways → "UTOPAY".
3. Paste the secret key (UTOPAY dashboard → Integration → API keys). Start with utopay_sk_test_… .
4. Payment options: card + crypto, card only or crypto only. Crypto coins: comma-separated tickers;
   add your wallet for those networks in the dashboard → Funds & payouts.
5. Open an unpaid invoice in the client area → "Pay by card / PayPal" → simulate a payment in the
   sandbox → the invoice becomes Paid (Billing → Gateway Log shows "Success").
6. Switch to the utopay_sk_live_… key.

NOTES
- Notifications need no setup: each payment carries its own callback URL
  (/modules/gateways/callback/utopay.php), signed and re-checked through the UTOPAY API.
- Invoice currency must be one UTOPAY accepts (USD EUR GBP CAD AUD … — see the guide), or set
  "Convert To For Processing" in the gateway settings (e.g. RUB invoices paid in USD). The invoice
  is credited in its own currency.
- Underpaid crypto payments are not applied automatically: see Billing → Gateway Log and add a
  partial payment manually.
- Refunds and recurring billing are not supported: each invoice is paid by the client.
