Discouraged Class Usage PHPCS

Let's say I have these classes:

• Old_Class
• New_Class

If this exists ->something(new Old_Class()) or Old_Class::staticMethod() or $oldClass->methodCall() I want a code sniff to warn "Old_Class usage found, recommend using New_Class instead".

I found this sniff Generic.PHP.ForbiddenFunctions but it only seems to catch built-in php functions is_array, is_null, etc.

Do I need to write a custom sniff for this?

If so, what token should I added to the register() function to catch on?

I couldn't use a built-in one. I had to write one using T_STRING.

public function register()
{
    return [
        T_STRING,
    ];
}

public function process(PHP_CodeSniffer_File $phpcsFile, $stackPtr)
{
    $tokens = $phpcsFile->getTokens();

    if ($tokens[$stackPtr]['content'] === 'Old_Class') {
        $error = 'Old_Class usage found, consider using New_Class instead.';
        $phpcsFile->addWarning($error, $stackPtr);
    }
}