oohhh… sorry about not checking the version earlier… Yeah… on local environment I use 3.14
root@aerospike:/# asinfo -v build
3.14.1.4
On live we use even lower - 3.12.1 All makes sense now.
Anyway thank you for the fruitful discussion - I will stick to the UDF implementation I have and some day if we upgrade our aerospikes I will have the reference here as well 
Thanks, Miroslav