add: disabled Testnet BTC API warning (#3830)

* add disabled btc warning

* Update docs/developer-docs/multi-chain/bitcoin/using-btc/btc-dev-workflow.mdx

* Update docs/developer-docs/multi-chain/bitcoin/using-btc/local-development.mdx

* Update docs/developer-docs/multi-chain/bitcoin/using-btc/submit-transactions.mdx

docs/developer-docs/multi-chain/bitcoin/using-btc/btc-dev-workflow.mdx

@@ -21,6 +21,14 @@ To interact with the Bitcoin testnet or mainnet networks, a developer needs to u
 
 1. [Generate a Bitcoin address](generate-addresses.mdx): To receive BTC, your canister must generate a Bitcoin address using the `ecdsa_public_key` API endpoint of the [management canister](/docs/current/developer-docs/smart-contracts/advanced-features/management-canister#signing-and-submitting-bitcoin-transactions).
 
+:::danger
+
+The Bitcoin Testnet API is currently disabled and the ckTestBTC minter canister has been stopped. This is temporary and they will be re-enabled in the future.
+
+[Learn more](https://forum.dfinity.org/t/direct-integration-with-bitcoin/6147/745).
+
+:::
+
 2. [Create a Bitcoin transaction](create-transactions.mdx): If the canister controls BTC, it can create a transaction to spend them.
 
 3. [Sign a transaction](sign-transactions.mdx): Next, the transaction must be signed with tECDSA using the `sign_with_ecdsa` API endpoint of the [management canister](/docs/current/developer-docs/smart-contracts/advanced-features/management-canister#signing-and-submitting-bitcoin-transactions). Transactions cannot be sent to the Bitcoin network until they are signed.

docs/developer-docs/multi-chain/bitcoin/using-btc/local-development.mdx

@@ -19,17 +19,26 @@ locally. Testing locally allows you to iterate and improve your dapp more quickl
 the [Bitcoin API](/docs/current/references/ic-interface-spec#ic-bitcoin-api)
 so that you can locally test out your dapp before deploying it to the Internet Computer.
 
+:::danger
+
+The Bitcoin Testnet API is currently disabled and the ckTestBTC minter canister has been stopped. This is temporary and they will be re-enabled in the future.
+
+[Learn more](https://forum.dfinity.org/t/direct-integration-with-bitcoin/6147/745).
+
+:::
+
 ## Setting up a local Bitcoin network
 
 To develop Bitcoin dapps locally, you'll need to set up a local Bitcoin network on your machine.
 Having your own local Bitcoin network allows you to mine blocks quickly and at-will, which
 facilitates testing various cases without having to rely on the (slow) Bitcoin testnet
 or the (even slower) Bitcoin mainnet.
 
-- #### Step 1: Download [Bitcoin core](https://bitcoin.org/en/download).  Mac users are recommended to download the `.tar.gz` version.
-- #### Step 2: Unpack the `.tar.gz` file.
-- #### Step 3: Create a directory named `data` inside the unpacked folder.
+- #### Step 1: Download [Bitcoin core v25](https://bitcoin.org/bin/bitcoin-core-25.0/). It is recommended to use the `.tar.gz` version for Mac users.
+- #### Step 2: Unpack the `.tar.gz` file: `tar -xfz bitcoin-25.0-x86_64-apple-darwin.tar.gz`
+- #### Step 3: Create a directory named `data` inside the unpacked folder: `cd bitcoin-25.0 && mkdir data`
 - #### Step 4: Create a file called `bitcoin.conf` at the root of the unpacked folder and add the following contents:
+
 ```
 # Enable regtest mode. This is required to setup a private bitcoin network.
 regtest=1

docs/developer-docs/multi-chain/bitcoin/using-btc/submit-transactions.mdx

@@ -20,6 +20,14 @@ To submit transactions to the Bitcoin network, the Bitcoin integration API expos
 
 The following snippet shows how to send a signed transaction to the Bitcoin network.
 
+:::danger
+
+The Bitcoin Testnet API is currently disabled and the ckTestBTC minter canister has been stopped. This is temporary and they will be re-enabled in the future.
+
+[Learn more](https://forum.dfinity.org/t/direct-integration-with-bitcoin/6147/745).
+
+:::
+
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