You might use the following command to check, whether your code uses deprecated jQuery calls removed in jQuery 4.
grep -RInE \
'((jQuery|\$)\.(isArray|parseJSON|trim|type|now|isNumeric|isFunction|isWindow|camelCase|nodeName|cssNumber|cssProps)|((jQuery|\$)\.fx\.interval))' \
/usr/local/oacs-head/openacs-4/packages/