Zend replacement in 2.4.6 – Rubin Shrestha

I have a theme and extensions that use widely the Zend_Json function
i.e.for example :
window.checkout = getConfig()); ?>;
in 2.4.5 I had no problem using this code, in 2.4.6 it throws an exception :
” main.CRITICAL: Error: Class “Zend_Json” not found in”
I have the laminas package…what can go wrong ?
TIA for help