# Revisiting BIP21 **URL:** \ **Category:** Implementation\ **Tags:** taproot, address, wallet\ **Created:** [March 1, 2024, 1:48pm UTC](https://delvingbitcoin.org/t/revisiting-bip21/630 "2024-03-01T13:48:06Z")\ **Posts on this page:** 1\ **Showing post:** 13
**Author:** ![MattCorallo](https://delvingbitcoin.org/letter_avatar_proxy/v4/letter/m/e47c2d/32.png) [@MattCorallo](https://delvingbitcoin.org/u/MattCorallo)\ **Post date:** [March 1, 2024, 6:23pm UTC](https://delvingbitcoin.org/t/revisiting-bip21/630/13 "2024-03-01T18:23:01Z")
> If they are requiring an `=` they aren’t spec compliant? 🙂 But agree, we don’t want to break anything. This is pretty easy to verify, though, since we have a good list of implementations listed at [https://bitcoinqr.dev/](https://bitcoinqr.dev/) which can be used to verify, and this is a somewhat trivial fix if they are requiring an `=`. Yea, I mean if someone wants to do the legwork I’d be happy to see the no-KV version, just not sure its worth someone’s time to do that :). > This seems less risky then specifying `bitcoin:?key=val`, which seems _more_ likely to break existing implementations since a spec compliant implementation _would_ expect an address in the root of the URI. The point of this is that it is _only_ done for new key types which are already, today, unsupported. So the options are bitcoin:newaddressformat or bitcoin:?k=newaddressformat. The same set of wallets is broken by both, at least as long as those adding support for newaddressformat support the empty-body version as a part of rolling out the upgrade. Luckily this is a bit easier to test - simply provide test cases for both in the BIP defining newaddressformat. Further, it seems marginally less likely to break for us to go from bitcoin:oldaddressformat?k=newaddressformat to bitcoin:?k=newaddressformat rather than bitcoin:newaddressformat, not to mention its just nice to only have one format/place to look for newaddressformat. Though, the same “people should test this as a part of the rollout” argument applies, of course. --- _[View the full topic](https://delvingbitcoin.org/t/revisiting-bip21/630)._