It should work. There is a behaviour change, though - the frontmatter now needs to be proper YAML, which means values can’t start with { otherwise they are read as empty dictionaries (YAML would support address: {street: Baker, number 221b} for example). So you have to change
key: {{value}}
to use quotes:
key: "{{value}}"
I’ve updated the docs to mention this, as it surprised me!
If that doesn’t work, though, there’s a problem