[Template] When you want to propose a Proposal


Write down the name of the proposal


Please write the background of the proposal here. It will be a description of what motivates you to make this proposal.

What is the purpose of the proposal? What would be the significance of the proposal if it was adopted?


The more details, the better. The specific motivation of the proposal, which can be further specified with images, code or links.

Example :point_down:

Polkassembly Proposal


#129 Increasing ump service limit threshold value

At current stage, the ump transact used by XCM cannot call the contribute function, due to the insufficient maximum weight of the ump service limit.

This proposal hence to increase the weight limit, in order to call more functions such as contribute, staking etc. Allowing more ump transacts means provide more flexibility & possibility to improve the flexibility of parachains, which benefits the use cases of Kusama ecology.


One of Bifrost service is to help other parachains to participate in crowdloan with assets locked while still providing the liquidity in the form of our staking derivatives. We use xcm transact to achieve it with contribution call constructed as following.

Xcm::WithdrawAsset {
      assets: vec![MultiAsset::ConcreteFungible {
        id: MultiLocation::Null,
        amount: contribution_amount,
      effects: vec![Order::BuyExecution {
        fees: MultiAsset::All,
        weight: contribution_weight,
        debt: contribution_debt,
        halt_on_error: true,
        xcm: vec![Xcm::Transact {
          origin_type: OriginKind::SovereignAccount,
          require_weight_at_most: contribution_weight_at_most,
          call: contribution_call,

But the current ump-service-weight threshold does not allow it and the call will just fail.