diff --git a/.github/workflows/monitor_requirements_size_master.yml b/.github/workflows/monitor_requirements_size_master.yml
index 301767ce7e..e9efa8dcd3 100644
--- a/.github/workflows/monitor_requirements_size_master.yml
+++ b/.github/workflows/monitor_requirements_size_master.yml
@@ -6,8 +6,8 @@ name: Monitor SDK Requirements Size
 
 on:
   pull_request:
-    types: [opened]
-    branches: [master]
+    types: [opened, labeled]
+    branches: [master, staging]
 
 permissions:
   pull-requests: write
@@ -15,6 +15,7 @@ permissions:
 
 jobs:
   measure-venv:
+    if: github.event_name == 'pull_request' && github.base_ref == 'master' || contains( github.event.pull_request.labels.*.name, 'show-venv-size')
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -54,7 +55,6 @@ jobs:
           esac
 
   comment-on-pr:
-    if: github.event_name == 'pull_request' && github.base_ref == 'master'
     needs: measure-venv
     runs-on: ubuntu-latest
     steps:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 69844e7def..1e7ccd6c02 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,15 @@
 # Changelog
 
+## 9.5.0 /2025-05-15
+
+* Add manual way to show the size of virtual environments in the PR by @basfroman in https://github.com/opentensor/bittensor/pull/2875
+* Improve `Monitor SDK Requirements Size` workflow by @basfroman in https://github.com/opentensor/bittensor/pull/2878
+* Add subtensor.is_subnet_active method by @basfroman in https://github.com/opentensor/bittensor/pull/2877
+* Using `hotkey` instead of `coldkey` to sign extrinsic in `serve_axon` by @basfroman in https://github.com/opentensor/bittensor/pull/2879
+* Rename argument `fallback_chains` to `fallback_endpoints` by @basfroman in https://github.com/opentensor/bittensor/pull/2880
+
+**Full Changelog**: https://github.com/opentensor/bittensor/compare/v9.5.0...v9.6.0
+
 ## 9.5.0 /2025-05-12
 
 ## What's Changed
diff --git a/bittensor/core/async_subtensor.py b/bittensor/core/async_subtensor.py
index 1402e4c683..0d99e887c3 100644
--- a/bittensor/core/async_subtensor.py
+++ b/bittensor/core/async_subtensor.py
@@ -115,7 +115,7 @@ def __init__(
         network: Optional[str] = None,
         config: Optional["Config"] = None,
         log_verbose: bool = False,
-        fallback_chains: Optional[list[str]] = None,
+        fallback_endpoints: Optional[list[str]] = None,
         retry_forever: bool = False,
         _mock: bool = False,
     ):
@@ -123,11 +123,11 @@ def __init__(
         Initializes an instance of the AsyncSubtensor class.
 
         Arguments:
-            network (str): The network name or type to connect to.
-            config (Optional[Config]): Configuration object for the AsyncSubtensor instance.
-            log_verbose (bool): Enables or disables verbose logging.
-            fallback_chains (list): List of fallback chains endpoints to use if no network is specified. Defaults to `None`.
-            retry_forever (bool): Whether to retry forever on connection errors. Defaults to `False`.
+            network: The network name or type to connect to.
+            config: Configuration object for the AsyncSubtensor instance.
+            log_verbose: Enables or disables verbose logging.
+            fallback_endpoints: List of fallback endpoints to use if default or provided network is not available. Defaults to `None`.
+            retry_forever: Whether to retry forever on connection errors. Defaults to `False`.
             _mock: Whether this is a mock instance. Mainly just for use in testing.
 
         Raises:
@@ -148,7 +148,9 @@ def __init__(
             f"chain_endpoint: [blue]{self.chain_endpoint}[/blue]..."
         )
         self.substrate = self._get_substrate(
-            fallback_chains=fallback_chains, retry_forever=retry_forever, _mock=_mock
+            fallback_endpoints=fallback_endpoints,
+            retry_forever=retry_forever,
+            _mock=_mock,
         )
         if self.log_verbose:
             logging.info(
@@ -284,24 +286,24 @@ async def get_hyperparameter(
 
     def _get_substrate(
         self,
-        fallback_chains: Optional[list[str]] = None,
+        fallback_endpoints: Optional[list[str]] = None,
         retry_forever: bool = False,
         _mock: bool = False,
     ) -> Union[AsyncSubstrateInterface, RetryAsyncSubstrate]:
         """Creates the Substrate instance based on provided arguments.
 
         Arguments:
-            fallback_chains (list): List of fallback chains endpoints to use if no network is specified. Defaults to `None`.
-            retry_forever (bool): Whether to retry forever on connection errors. Defaults to `False`.
+            fallback_endpoints: List of fallback endpoints to use if default or provided network is not available. Defaults to `None`.
+            retry_forever: Whether to retry forever on connection errors. Defaults to `False`.
             _mock: Whether this is a mock instance. Mainly just for use in testing.
 
         Returns:
             the instance of the SubstrateInterface or RetrySyncSubstrate class.
         """
-        if fallback_chains or retry_forever:
+        if fallback_endpoints or retry_forever:
             return RetryAsyncSubstrate(
                 url=self.chain_endpoint,
-                fallback_chains=fallback_chains,
+                fallback_chains=fallback_endpoints,
                 ss58_format=SS58_FORMAT,
                 type_registry=TYPE_REGISTRY,
                 retry_forever=retry_forever,
@@ -2582,6 +2584,35 @@ async def is_hotkey_registered_on_subnet(
             is not None
         )
 
+    async def is_subnet_active(
+        self,
+        netuid: int,
+        block: Optional[int] = None,
+        block_hash: Optional[str] = None,
+        reuse_block: bool = False,
+    ) -> bool:
+        """Verify if subnet with provided netuid is active.
+
+        Args:
+            netuid (int): The unique identifier of the subnet.
+            block (Optional[int]): The blockchain block number for the query.
+            block_hash (Optional[str]): The blockchain block_hash representation of block id.
+            reuse_block (bool): Whether to reuse the last-used block hash.
+
+        Returns:
+            True if subnet is active, False otherwise.
+
+        This means whether the `start_call` was initiated or not.
+        """
+        query = await self.query_subtensor(
+            name="FirstEmissionBlockNumber",
+            block=block,
+            block_hash=block_hash,
+            reuse_block=reuse_block,
+            params=[netuid],
+        )
+        return True if query and query.value > 0 else False
+
     async def last_drand_round(self) -> Optional[int]:
         """
         Retrieves the last drand round emitted in bittensor. This corresponds when committed weights will be revealed.
diff --git a/bittensor/core/extrinsics/asyncex/serving.py b/bittensor/core/extrinsics/asyncex/serving.py
index c37c612191..b942a88dc1 100644
--- a/bittensor/core/extrinsics/asyncex/serving.py
+++ b/bittensor/core/extrinsics/asyncex/serving.py
@@ -61,6 +61,7 @@ async def do_serve_axon(
         wallet=wallet,
         wait_for_inclusion=wait_for_inclusion,
         wait_for_finalization=wait_for_finalization,
+        sign_with="hotkey",
         period=period,
     )
     return success, message
@@ -140,7 +141,7 @@ async def serve_extrinsic(
         f"Serving axon with: [blue]AxonInfo({wallet.hotkey.ss58_address}, {ip}:{port})[/blue] -> "
         f"[green]{subtensor.network}:{netuid}[/green]"
     )
-    success, message = do_serve_axon(
+    success, message = await do_serve_axon(
         subtensor=subtensor,
         wallet=wallet,
         call_params=params,
diff --git a/bittensor/core/extrinsics/serving.py b/bittensor/core/extrinsics/serving.py
index d004fd7dba..b49196bf89 100644
--- a/bittensor/core/extrinsics/serving.py
+++ b/bittensor/core/extrinsics/serving.py
@@ -60,6 +60,7 @@ def do_serve_axon(
         wallet=wallet,
         wait_for_inclusion=wait_for_inclusion,
         wait_for_finalization=wait_for_finalization,
+        sign_with="hotkey",
         period=period,
     )
     return success, message
diff --git a/bittensor/core/subtensor.py b/bittensor/core/subtensor.py
index 63634d9053..5e356f9666 100644
--- a/bittensor/core/subtensor.py
+++ b/bittensor/core/subtensor.py
@@ -117,7 +117,7 @@ def __init__(
         network: Optional[str] = None,
         config: Optional["Config"] = None,
         log_verbose: bool = False,
-        fallback_chains: Optional[list[str]] = None,
+        fallback_endpoints: Optional[list[str]] = None,
         retry_forever: bool = False,
         _mock: bool = False,
     ):
@@ -125,11 +125,11 @@ def __init__(
         Initializes an instance of the Subtensor class.
 
         Arguments:
-            network (str): The network name or type to connect to.
-            config (Optional[Config]): Configuration object for the AsyncSubtensor instance.
-            log_verbose (bool): Enables or disables verbose logging.
-            fallback_chains (list): List of fallback chains endpoints to use if no network is specified. Defaults to `None`.
-            retry_forever (bool): Whether to retry forever on connection errors. Defaults to `False`.
+            network: The network name or type to connect to.
+            config: Configuration object for the AsyncSubtensor instance.
+            log_verbose: Enables or disables verbose logging.
+            fallback_endpoints: List of fallback endpoints to use if default or provided network is not available. Defaults to `None`.
+            retry_forever: Whether to retry forever on connection errors. Defaults to `False`.
             _mock: Whether this is a mock instance. Mainly just for use in testing.
 
         Raises:
@@ -148,7 +148,9 @@ def __init__(
             f"chain_endpoint: [blue]{self.chain_endpoint}[/blue]> ..."
         )
         self.substrate = self._get_substrate(
-            fallback_chains=fallback_chains, retry_forever=retry_forever, _mock=_mock
+            fallback_endpoints=fallback_endpoints,
+            retry_forever=retry_forever,
+            _mock=_mock,
         )
         if self.log_verbose:
             logging.info(
@@ -167,28 +169,28 @@ def close(self):
 
     def _get_substrate(
         self,
-        fallback_chains: Optional[list[str]] = None,
+        fallback_endpoints: Optional[list[str]] = None,
         retry_forever: bool = False,
         _mock: bool = False,
     ) -> Union[SubstrateInterface, RetrySyncSubstrate]:
         """Creates the Substrate instance based on provided arguments.
 
         Arguments:
-            fallback_chains (list): List of fallback chains endpoints to use if no network is specified. Defaults to `None`.
-            retry_forever (bool): Whether to retry forever on connection errors. Defaults to `False`.
+            fallback_endpoints: List of fallback chains endpoints to use if main network isn't available. Defaults to `None`.
+            retry_forever: Whether to retry forever on connection errors. Defaults to `False`.
             _mock: Whether this is a mock instance. Mainly just for use in testing.
 
         Returns:
             the instance of the SubstrateInterface or RetrySyncSubstrate class.
         """
-        if fallback_chains or retry_forever:
+        if fallback_endpoints or retry_forever:
             return RetrySyncSubstrate(
                 url=self.chain_endpoint,
                 ss58_format=SS58_FORMAT,
                 type_registry=TYPE_REGISTRY,
                 use_remote_preset=True,
                 chain_name="Bittensor",
-                fallback_chains=fallback_chains,
+                fallback_chains=fallback_endpoints,
                 retry_forever=retry_forever,
                 _mock=_mock,
             )
@@ -2023,6 +2025,25 @@ def is_hotkey_registered_on_subnet(
             is not None
         )
 
+    def is_subnet_active(self, netuid: int, block: Optional[int] = None) -> bool:
+        """Verify if subnet with provided netuid is active.
+
+        Args:
+            netuid (int): The unique identifier of the subnet.
+            block (Optional[int]): The blockchain block number for the query.
+
+        Returns:
+            True if subnet is active, False otherwise.
+
+        This means whether the `start_call` was initiated or not.
+        """
+        query = self.query_subtensor(
+            name="FirstEmissionBlockNumber",
+            block=block,
+            params=[netuid],
+        )
+        return True if query and query.value > 0 else False
+
     def last_drand_round(self) -> Optional[int]:
         """
         Retrieves the last drand round emitted in bittensor. This corresponds when committed weights will be revealed.
diff --git a/bittensor/core/subtensor_api/__init__.py b/bittensor/core/subtensor_api/__init__.py
index be5a61638a..2d021cd1ce 100644
--- a/bittensor/core/subtensor_api/__init__.py
+++ b/bittensor/core/subtensor_api/__init__.py
@@ -25,9 +25,9 @@ class SubtensorApi:
         network: The network to connect to. Defaults to `None` -> "finney".
         config: Bittensor configuration object. Defaults to `None`.
         legacy_methods: If `True`, all methods from the Subtensor class will be added to the root level of this class.
-        fallback_chains (list): List of fallback chains to use if no network is specified. Defaults to `None`.
-        retry_forever (bool): Whether to retry forever on connection errors. Defaults to `False`.
-        log_verbose (bool): Enables or disables verbose logging.
+        fallback_endpoints: List of fallback endpoints to use if default or provided network is not available. Defaults to `None`.
+        retry_forever: Whether to retry forever on connection errors. Defaults to `False`.
+        log_verbose: Enables or disables verbose logging.
         mock: Whether this is a mock instance. Mainly just for use in testing.
 
     Example:
@@ -54,10 +54,15 @@ class SubtensorApi:
         subtensor = bt.SubtensorApi(legacy_methods=True)
         print(subtensor.bonds(0))
 
-        # using `fallback_chains` or `retry_forever`
+        # using `fallback_endpoints` or `retry_forever`
         import bittensor as bt
 
-
+        subtensor = bt.SubtensorApi(
+            network="finney",
+            fallback_endpoints=["wss://localhost:9945", "wss://some-other-endpoint:9945"],
+            retry_forever=True,
+        )
+        print(subtensor.block)
     """
 
     def __init__(
@@ -66,13 +71,13 @@ def __init__(
         config: Optional["Config"] = None,
         async_subtensor: bool = False,
         legacy_methods: bool = False,
-        fallback_chains: Optional[list[str]] = None,
+        fallback_endpoints: Optional[list[str]] = None,
         retry_forever: bool = False,
         log_verbose: bool = False,
         mock: bool = False,
     ):
         self.network = network
-        self._fallback_chains = fallback_chains
+        self._fallback_endpoints = fallback_endpoints
         self._retry_forever = retry_forever
         self._mock = mock
         self.log_verbose = log_verbose
@@ -111,7 +116,7 @@ def _get_subtensor(self) -> Union["_Subtensor", "_AsyncSubtensor"]:
                 network=self.network,
                 config=self._config,
                 log_verbose=self.log_verbose,
-                fallback_chains=self._fallback_chains,
+                fallback_endpoints=self._fallback_endpoints,
                 retry_forever=self._retry_forever,
                 _mock=self._mock,
             )
@@ -122,7 +127,7 @@ def _get_subtensor(self) -> Union["_Subtensor", "_AsyncSubtensor"]:
                 network=self.network,
                 config=self._config,
                 log_verbose=self.log_verbose,
-                fallback_chains=self._fallback_chains,
+                fallback_endpoints=self._fallback_endpoints,
                 retry_forever=self._retry_forever,
                 _mock=self._mock,
             )
diff --git a/bittensor/core/subtensor_api/subnets.py b/bittensor/core/subtensor_api/subnets.py
index c3333daf30..8b8c9121e7 100644
--- a/bittensor/core/subtensor_api/subnets.py
+++ b/bittensor/core/subtensor_api/subnets.py
@@ -32,6 +32,7 @@ def __init__(self, subtensor: Union["_Subtensor", "_AsyncSubtensor"]):
         self.get_uid_for_hotkey_on_subnet = subtensor.get_uid_for_hotkey_on_subnet
         self.immunity_period = subtensor.immunity_period
         self.is_hotkey_registered_on_subnet = subtensor.is_hotkey_registered_on_subnet
+        self.is_subnet_active = subtensor.is_subnet_active
         self.max_weight_limit = subtensor.max_weight_limit
         self.min_allowed_weights = subtensor.min_allowed_weights
         self.recycle = subtensor.recycle
diff --git a/bittensor/core/subtensor_api/utils.py b/bittensor/core/subtensor_api/utils.py
index fdfde50697..3f8cc7d36d 100644
--- a/bittensor/core/subtensor_api/utils.py
+++ b/bittensor/core/subtensor_api/utils.py
@@ -108,6 +108,7 @@ def add_legacy_methods(subtensor: "SubtensorApi"):
     subtensor.is_hotkey_registered_on_subnet = (
         subtensor._subtensor.is_hotkey_registered_on_subnet
     )
+    subtensor.is_subnet_active = subtensor._subtensor.is_subnet_active
     subtensor.last_drand_round = subtensor._subtensor.last_drand_round
     subtensor.log_verbose = subtensor._subtensor.log_verbose
     subtensor.max_weight_limit = subtensor._subtensor.max_weight_limit
diff --git a/pyproject.toml b/pyproject.toml
index a9b9db6a01..4b3d8fbe99 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "bittensor"
-version = "9.5.0"
+version = "9.6.0"
 description = "Bittensor"
 readme = "README.md"
 authors = [
diff --git a/tests/e2e_tests/utils/e2e_test_utils.py b/tests/e2e_tests/utils/e2e_test_utils.py
index 745c8977ab..8e5254535f 100644
--- a/tests/e2e_tests/utils/e2e_test_utils.py
+++ b/tests/e2e_tests/utils/e2e_test_utils.py
@@ -229,7 +229,7 @@ def validator(self, wallet, netuid):
 
 
 def wait_to_start_call(
-    subtensor: "bittensor.Subtensor",
+    subtensor: "bittensor.SubtensorApi",
     subnet_owner_wallet: "bittensor.Wallet",
     netuid: int,
     in_blocks: int = 10,
@@ -242,6 +242,11 @@ def wait_to_start_call(
         f"Current block: [blue]{subtensor.block}[/blue]."
     )
 
+    # make sure subnet isn't active
+    assert subtensor.subnets.is_subnet_active(netuid) is False, (
+        "Subnet is already active."
+    )
+
     # make sure we passed start_call limit
     subtensor.wait_for_block(subtensor.block + in_blocks + 1)
     status, message = subtensor.start_call(
@@ -251,6 +256,11 @@ def wait_to_start_call(
         wait_for_finalization=True,
     )
     assert status, message
+    # make sure subnet is active
+    assert subtensor.subnets.is_subnet_active(netuid), (
+        "Subnet did not activated after start call."
+    )
+
     return True
 
 
diff --git a/tests/unit_tests/test_subtensor.py b/tests/unit_tests/test_subtensor.py
index 9085bf1122..b1020d7648 100644
--- a/tests/unit_tests/test_subtensor.py
+++ b/tests/unit_tests/test_subtensor.py
@@ -1492,6 +1492,7 @@ def test_do_serve_axon_is_success(
         wallet=fake_wallet,
         wait_for_inclusion=fake_wait_for_inclusion,
         wait_for_finalization=fake_wait_for_finalization,
+        sign_with="hotkey",
         period=None,
     )
 
@@ -1530,6 +1531,7 @@ def test_do_serve_axon_is_not_success(subtensor, fake_wallet, mocker, fake_call_
         wallet=fake_wallet,
         wait_for_inclusion=fake_wait_for_inclusion,
         wait_for_finalization=fake_wait_for_finalization,
+        sign_with="hotkey",
         period=None,
     )
 
@@ -1568,6 +1570,7 @@ def test_do_serve_axon_no_waits(subtensor, fake_wallet, mocker, fake_call_params
         wallet=fake_wallet,
         wait_for_inclusion=fake_wait_for_inclusion,
         wait_for_finalization=fake_wait_for_finalization,
+        sign_with="hotkey",
         period=None,
     )
     assert result == (True, "")
@@ -3633,3 +3636,32 @@ def test_get_subnet_validator_permits_is_none(subtensor, mocker):
     )
 
     assert result is None
+
+
+@pytest.mark.parametrize(
+    "query_return, expected",
+    [
+        [111, True],
+        [0, False],
+    ],
+)
+def test_is_subnet_active(subtensor, mocker, query_return, expected):
+    # preps
+    netuid = mocker.Mock()
+    block = mocker.Mock()
+    mocked_query_subtensor = mocker.MagicMock(
+        return_value=mocker.Mock(value=query_return)
+    )
+    subtensor.query_subtensor = mocked_query_subtensor
+
+    # call
+    result = subtensor.is_subnet_active(netuid=netuid, block=block)
+
+    # Asserts
+    mocked_query_subtensor.assert_called_once_with(
+        name="FirstEmissionBlockNumber",
+        block=block,
+        params=[netuid],
+    )
+
+    assert result == expected