This referendum is meant for enabling async-backing on polkadot, more information about what is async backing and what this parameter changes will do can be found here async backing

All async backing logic will be enabled with polkadot runtime upgrade 1.2.0, but in sync mode, parachains can produce block only at 12s rate.

After this referendum parachains can decide to produce blocks at 6s rate, by following this guide https://wiki.polkadot.network/docs/maintain-guides-async-backing, but that is not mandatory, they will still run at 12s rate without any changes needed on their side.

Whitelisted by: https://collectives.subsquare.io/fellowship/referenda/102.

Testing done

Async backing has been running on Rococo since December 2023 and on Westend since February 2024 with all system parachains migrated to produce blocks at 6s rate and on kusama after https://kusama.subsquare.io/referenda/374

Our final checklist enablement can be found here: https://github.com/paritytech/polkadot-sdk/issues/3226

Dependencies

• Async backing runtime APIs come in polkadot runtime v1.2, which will get enacted with: https://polkadot.subsquare.io/referenda/648, this referendum needs to be enacted after that.

Known issues

No critical issues are known at this moment, however to make the transition smooth all validators need to be upgraded to a version higher that v1.8. There are still around 3-5% validators in the active set that are not upgraded, so when it is their turn to back they won't back anything, and if 3 out of 5 nodes are in the same backing group the group won't be able to back the candidates it is assigned to. Action Un-upgraded validators please upgrade to something higher than 1.8 node version.