# Convert and replace the value of an input field.
# ({$date:"..."} is Mongo's Extended BSON syntax.)

echo '{"version":1,"account_id":"123","country":"DE","currency":"EUR","date":"2010-07-13T14:27:00"}' | \
  jq -rc \
    '. | . + { date: { "$date": "\(.date).0000000Z" } }'

# Output
# {"version":1,"account_id":"123","country":"DE","currency":"EUR","date":{"$date":"2010-07-13T14:27:00.0000000Z"}}