Missing Aurora Function after upgrade from aurora pg 12 to pg 13

Hello,

We recently upgraded from aurora pg 12.4 to aurora 13.4 and after that, we noticed that this query stopped working,

select sum(allocated) from aurora_stat_memctx_usage()

I did not see anything in the change log about this method going away, but I'm unable to call it on any of our aurora 13.4 instances, but it works fine on our aurora 12.4 instance.

Any help would be appreciated.