# B-2.0 (BTC-Only)

BTC-Only firmware B-2.0 includes the updates below:

1\. Keystone now supports Casa, a key management protocol, in multi-signature wallet mode.

2\. The labeling of the firmware versions scheme has changed. M-x.x stands for "Multi-cion firmware" while B-x.x stands for "Bitcoin-only firmware".

Instructions recommended:

{% content-ref url="../../3rd-party-wallets/bitcoin-wallets/casa" %}
[casa](https://support.keyst.one/3rd-party-wallets/bitcoin-wallets/casa)
{% endcontent-ref %}