The proposal addresses a recent XCM issue where the `SetTopic` instruction in XCM programs conflicts with destinations set to default version 2. This mismatch lead to failed transactions. [Referendum 305](https://kusama.subsquare.io/referenda/305) has successfully resolved the issue on Kusama. Now, this proposal sets its sights on Polkadot's relay chain, advocating for a similar adjustment by aligning the `safeXcmVersion` to v3 and ensuring it sends XCMs in the v3 format by default.

The mismatch in XCM versions can lead to issues between the relay chain and parachains. To resolve this, we propose setting the relay chain's safeXcmVersion to v3. This adjustment ensures that the relay chain will send XCMs in the v3 format by default.

Note that the proposal has been submitted on the Whitelisted Caller track, meaning the Fellowship is also voting on a proposal (no. [56](https://collectives.subsquare.io/fellowship/referenda/56)) to whitelist the submission hash

See [`Pallet::dispatch_whitelisted_call_with_preimage`].

- **Problem Statement:** Addressing conflicts between XCM programs and default destinations due to mismatched versions, impacting transaction success.
- **Significance:** Ensuring alignment of safeXcmVersion to v3 on Polkadot's relay chain to prevent issues between the relay chain and parachains.
- **Proposed Solution:** Adjusting the relay chain's safeXcmVersion to v3 to send XCMs in the v3 format by default.
- **Expected Outcomes:** Resolution of XCM version mismatches, enhancing transaction success and interoperability within the Polkadot ecosystem.

#380 Setting the relay chain's safeXcmVersion to v3