cPanel 110 PHP Version Selector defaulting to 8.3: how should integration tests handle the change?

Context

With cPanel & WHM 110, the PHP Version Selector defaults to PHP 8.3 for newly provisioned accounts, while existing accounts keep their previously selected version. This creates a split behavior that automated integration tests need to account for.

The problem

A test suite that provisions fresh accounts and then validates application behavior against the account's PHP runtime can no longer assume a fixed default version. Tests written when the default was an older PHP branch may either test against the wrong runtime or fail outright if they hardcode a binary path or parse the default version from uAPI output. Because existing and new accounts behave differently after the upgrade, a single test environment may not represent both cases.

Constraints

The tests should run without production credentials, ideally against a fresh cPanel 110 installation or trial license. Version changes through uAPI require appropriate permissions, so the tests cannot silently switch runtimes mid-run. Verification of the actual default can be done with whmapi1 php_get_installed_versions or via the WHM "Select PHP Version" interface.

Questions

• Should integration tests explicitly pin a PHP version per account at provisioning time, or discover and adapt to the default at runtime?
• Is there a supported way to change the server-wide default for new accounts so test fixtures stay deterministic across cPanel upgrades?
• How are teams covering both the "upgraded existing account" and "fresh account on 8.3" paths in one suite?