PHP Version Support Matrix
From WHMCS Documentation
| WHMCS Version (Status) | PHP v5.2 | PHP v5.3 | PHP v5.4 | PHP v5.6 | PHP v7.0 | PHP v7.1 | PHP v7.2 | PHP v7.3 | PHP v7.4 | PHP v8.1 |
|---|---|---|---|---|---|---|---|---|---|---|
| v6.3 (EOL) | Y | Y | Y | Y | N | N | N | N | N | N |
| v7.0 (EOL) | N | N | N | Y | Y | N | N | N | N | N |
| v7.1 (EOL) | N | N | N | Y | Y | N | N | N | N | N |
| v7.2 (EOL) | N | N | N | Y | Y | N | N | N | N | N |
| v7.3 (EOL) | N | N | N | Y | Y | N | N | N | N | N |
| v7.4 (EOL) | N | N | N | Y | Y | N | N | N | N | N |
| v7.5 (EOL) | N | N | N | Y | Y | Y | Y | N | N | N |
| v7.6 (EOL) | N | N | N | Y | Y | Y | Y | Y | N | N |
| v7.7 (EOL) | N | N | N | Y | Y | Y | Y | Y | N | N |
| v7.8 (EOL) | N | N | N | Y | Y | Y | Y | Y | N | N |
| v7.9 (EOL) | N | N | N | Y | Y | Y | Y | Y | N | N |
| v7.10 (EOL) | N | N | N | Y | Y | Y | Y | Y | N | N |
| v8.0 (EOL) | N | N | N | N | N | N | Y | Y | Y | N |
| v8.1 (EOL) | N | N | N | N | N | N | Y | Y | Y | N |
| v8.2 (EOL) | N | N | N | N | N | N | Y | Y | Y | N |
| v8.3 (EOL) | N | N | N | N | N | N | Y | Y | Y | N |
| v8.4 (LTS) | N | N | N | N | N | N | Y | Y | Y | N |
| v8.5 (LTS) | N | N | N | N | N | N | Y | Y | Y | N |
| v8.6 (Active) | N | N | N | N | N | N | Y | Y | Y | Y |