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Bittensor 9.0 Migration Guide

This page notes breaking changes for the Bittensor Python SDK v9.0. This version supports Dynamic TAO, a major evolution of the Bittensor network's tokenomic architecture.

See: Dynamic TAO: What to expect.

Contents:

See: Concurrency with AyncIO and AsyncSubtensor

Subtensor: removed functions​

get_account_next_index​

This was only used for getting nonce, which can be achieved with subtensor.substrate.get_account_next_index(hotkey.ss58_address).

get_prometheus_info​

We no longer use prometheus info.

get_total_stake_for_coldkey​

Not compatible with Dynamic TAO.

Replaced with get_stake, which returns a staked balance for a coldkey, hotkey pair on a specific subnet.

get_total_stake_for_coldkeys​

Not compatible with Dynamic TAO.

Replaced with get_stake, which returns a staked balance for a coldkey, hotkey pair on a specific subnet.

get_total_stake_for_hotkey​

Not compatible with Dynamic TAO.

Replaced with get_stake, which returns a staked balance for a coldkey, hotkey pair on a specific subnet.

get_total_stake_for_hotkeys​

Not compatible with Dynamic TAO.

Replaced with get_stake, which returns a staked balance for a coldkey, hotkey pair on a specific subnet.

Subtensor: type changes​

__init__​

No longer takes connection_timeout or websocket args. This is due to py-substrate-interface being re-written as async-substrate-interface.

amount​

All Subtensor methods that accept an amount arg now accept it only as a Balance object, rather than the previous Union[Balance, int, float].

New helper functions, tao and rao in bittensor.utils.balance, return a balance object from the given Tao or Rao amount.

These methods include the following, and their associated extrinsics:

  • transfer
  • unstake
  • add_stake
  • move_stake
  • swap_stake
  • transfer_stake
  • get_transfer_fee

For example, where transfer previously accepted float for the amount, it now takes a Balance object, which can be created on the fly:

Previously:

from bittensor.core.subtensor import Subtensor

subtensor = Subtensor()
subtensor.transfer(wallet, destination, 1.0)

Now written as:

from bittensor.core.subtensor import Subtensor
from bittensor.utils.balance import tao, rao

subtensor = Subtensor()
subtensor.transfer(wallet, destination, tao(1.0))
# or
subtensor.transfer(wallet, destination, rao(1000000000))

consolidation of arg label: block​

There were some cases where the block arg was called block_number or block_id. This is standardised, and now all block args are called block.

get_block_hash​

No longer requires block arg, will fetch the latest block if not specified.

get_stake_for_coldkey_and_hotkey​

Arg order has changed. It now takes (coldkey, hotkey) to align with the method name.

In addition, to accomodate changes to staking in dynamic TAO, the function now also accepts an optional list of netuids to check for stake, and returns a dict[int, StakeInfo], where int is the netuid. If netuids is left as None, all netuids are fetched.

get_subnet_reveal_period_epochs​

Type hint is updated to reflect it always returns an int, rather than an Optional[int].

query_runtime_api​

Now accepts params as Any, returns Any. This is due to an update in bt-decode and async-substrate-interface that allows for arbitrary decoding of runtime calls.

get_subnet_burn_cost​

Now returns an Optional[Balance] object rather than Optional[int] (previously it gave rao int)

get_children​

Now returns tuple[bool, list[tuple[float, str]], str] instead of tuple[bool, list[tuple[int, str]], str], as the proportions are now normalised floats.

AsyncSubtensor​

AsyncSubtensor and Subtensor now have all and only the same methods.

Check out the wiki entry on Concurrency in Bittensor to learn more.

py-substrate-interface replaced with async-substrate-interface​

py-substrate-interface has been completely removed as a requirement, and has been rewritten as async-substrate-interface.

While the main goal of this project was initially just providing an AsyncIO-compatible version of py-substrate-interface for our use in btcli and AsyncSubtensor, we noticed a lot of room for improvement, so we wrote not only the async part, but also a synchronous part. We aimed to be as API-compatible as possible, but there are a few differences (mainly in runtime calls).

async-substrate-interface is its own standalone package, as is a requirement for bittensor and btcli, replacing py-substrate-interface.

While we do practically all the decoding now through bt-decode, we still use py-scale-codec for a few SCALE encodings. This package will also eventually be replaced by an updated version of bt-decode.

Check out the wiki entry on Concurrency in Bittensor to learn more.