With the upcoming Asset Hub Migration (AHM), parachains are expected to switch their KSM/DOT reserves from the Relay Chain to Asset Hub. This transition will occur at different times for different chains, which may disrupt cross-chain transfers in dapps for a period of time.
Some chains will have updated their reserves already, configured their runtimes and moved the funds from their sovereign accounts, as explained in this article. Other chains might transition after the migration, with varying timeframes depending on technical complexities specific to them.
The problem
Given this landscape, dapps must be prepared for chains transitioning their reserves for DOT at different times. Since we previously found an issue with automatically determining the reserve on the runtimes, dapps now need to manually specify the reserve they want to use and this becomes particularly relevant.
There are now two potential failure scenarios:
- If a dapp wants to use the Relay as the reserve but the chain it’s interacting with already transitioned to Asset Hub, the transfer will fail.
- If a dapp wants to use Asset Hub but the chain has not yet transitioned then the transfer will fail as well.
Proposed solution
Our proposed solution is to provide dapps with a mechanism to dynamically determine the correct reserve. This will allow them to identify whether the particular chain they’re interacting with has completed the transition.
Karol has developed a PoC of this mechanism to dynamically determine reserves: GitHub - karolk91/polkadot-remote-reserve-transfer-with-discovery: Polkadot related Typescript project based on PAPI and chopsticks libraries to showcase reserve based transfers from one chain to another using remote reserve .
The PoC is meant to help dapp developers implement the mechanism.
Paraspell’s XCM SDKs will also feature this mechanism. Dapps using their SDKs will have this available a few days prior to the Kusama migration in the latest version of the package they are using. If you have any questions or need any help with their tools, join their support channel.
Timeline
The migration timeline is as follows:
- The AHM for Kusama is scheduled for the 7th of October at 11:59 AM UTC.
- The AHM for Polkadot is scheduled for the 4th of November, exact time to be determined.
Call to action
We encourage dapp developers to:
- Review the reserve discovery mechanism
- Plan to integrate this solution before the migration, either via looking at the PoC or using Paraspell
- Test their dapps with both reserve configurations
If you have questions or need assistance with implementation, please join our Telegram support channel.
By implementing this mechanism for dynamic reserve discovery, we aim to minimize the disruption to cross-chain transfers during this post-migration period where chains are still transitioning their reserves.