Multisort flag doesn't seem to work The multisort flag for arrays doesn't work the way I'm trying it. This is how I'm using it.

{% for conv in conversations|multisort(['postDate'],['SORT_DESC']) %}

This is the error I keep getting.

array_multisort(): Argument #2 is expected to be an array or a sort flag

Any ideas?
I think you should change ['SORT_DESC'] to [SORT_DESC]. See this tweet for an example. SORT_DESC is a PHP constant, not a string.