New status SIGNED for charge

A few days ago appeared new status SIGNED for charges. Also, it's not described [here](https://docs.cloud.coinbase.com/commerce/docs/payment-status).
How to interpret this status?
Code used
```
client = CoinbaseCommerce::Client.new(api_key: COINBASE_API_KEY)
client.charge.retrieve(charge_id)[:timeline].last[:status]
```

Also, it started to return an error on charge creation if `local_price.currency = 'usd'`. Before it worked with lower case, now it accepts only upper case 'USD'.
```
client.charge.create(
local_price: {
amount: payment.calculate_amount,
currency: payment.currency.upcase
},
...
)
```

coinbase_commerce (0.8.7)
rails (6.1.3.1)
ruby 2.7.7p221