# update-crowdloan-min-contribution (/docs/tx/update-crowdloan-min-contribution)

Changes the smallest contribution the crowdloan will accept from that
point on; contributions already made are unaffected. Only the creator may
change it, and only while the loan has not been finalized.

| Signer    | Origin                                 | Pallet    | Wraps                                                                               |
| --------- | -------------------------------------- | --------- | ----------------------------------------------------------------------------------- |
| `coldkey` | signed account (pallet role may apply) | Crowdloan | [`Crowdloan.update_min_contribution`](/code/pallets/crowdloan/src/lib.rs#L817-L852) |

## Parameters [#parameters]

| Parameter                  | Type              | Required | Description                                                |
| -------------------------- | ----------------- | -------- | ---------------------------------------------------------- |
| `crowdloan_id`             | integer           | yes      | Identifier of the crowdloan, assigned when it was created. |
| `new_min_contribution_tao` | number \| `"all"` | yes      | New smallest contribution the crowdloan will accept.       |

Address parameters (`--hotkey`, `--coldkey`, `--dest`, ...) accept a raw ss58
address, an address-book or proxy-book name, or a local wallet/hotkey name.

## CLI [#cli]

Preview with `--dry-run` (shows fee, effects, and policy result without
submitting), then submit:

```bash
btcli tx update-crowdloan-min-contribution \
  --crowdloan-id <int> \
  --new-min-contribution-tao <amount|all> --dry-run
btcli tx update-crowdloan-min-contribution \
  --crowdloan-id <int> \
  --new-min-contribution-tao <amount|all> -w my_coldkey
```

## Python [#python]

```python
import bittensor as bt
from bittensor.wallet import Wallet

wallet = Wallet(name="my_coldkey", hotkey="my_hotkey")
intent = bt.UpdateCrowdloanMinContribution(crowdloan_id=0, new_min_contribution_tao=1.0)

sub = bt.Subtensor()
plan = sub.plan(intent, wallet)   # fee, effects, policy — no submission
result = sub.execute(intent, wallet)
if not result.success:
    print(result.error.code, result.error.remediation)
```

(`bt.Subtensor` is also the async client — `async with bt.Subtensor() as client:`
— see [The client](/docs/concepts/client).) Or build the intent by op name, as
an agent would:

```python
result = sub.execute_tool("update_crowdloan_min_contribution", {...}, wallet)
```

## On-chain implementation [#on-chain-implementation]

`Crowdloan.update_min_contribution` — [`pallets/crowdloan/src/lib.rs#L819`](/code/pallets/crowdloan/src/lib.rs#L817-L852):

```rust
#[pallet::call_index(6)]
#[pallet::weight(T::WeightInfo::update_min_contribution())]
pub fn update_min_contribution(
    origin: OriginFor<T>,
    #[pallet::compact] crowdloan_id: CrowdloanId,
    #[pallet::compact] new_min_contribution: BalanceOf<T>,
) -> DispatchResult {
    let who = ensure_signed(origin)?;

    let mut crowdloan = Self::ensure_crowdloan_exists(crowdloan_id)?;
    ensure!(!crowdloan.finalized, Error::<T>::AlreadyFinalized);

    // Only the creator can update the min contribution.
    ensure!(who == crowdloan.creator, Error::<T>::InvalidOrigin);

    // The new min contribution should be greater than absolute minimum contribution.
    ensure!(
        new_min_contribution >= T::AbsoluteMinimumContribution::get(),
        Error::<T>::MinimumContributionTooLow
    );
    if let Some(max_contribution) = MaxContributions::<T>::get(crowdloan_id) {
        ensure!(
            new_min_contribution <= max_contribution,
            Error::<T>::MinimumContributionTooHigh
        );
    }

    crowdloan.min_contribution = new_min_contribution;
    Crowdloans::<T>::insert(crowdloan_id, &crowdloan);

    Self::deposit_event(Event::<T>::MinContributionUpdated {
        crowdloan_id,
        new_min_contribution,
    });
    Ok(())
}
```

Every file is browsable under [/code](/code) exactly as built into the runtime, or as plain text under `/code/raw/<path>` (index: [`/code/index.json`](/code/index.json)).