# Blocking CairoZero Class Declarations

**URL:** <https://community.starknet.io/t/blocking-cairozero-class-declarations/113807>\
**Category:** 🆙 Versions Upgrade\
**Created:** [March 25, 2024, 12:15pm UTC](https://community.starknet.io/t/blocking-cairozero-class-declarations/113807 "2024-03-25T12:15:11Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![ilia](https://dub1.discourse-cdn.com/flex005/user_avatar/community.starknet.io/ilia/32/1318_2.png) [@ilia](https://community.starknet.io/u/ilia)\
**Post date:** [March 25, 2024, 12:15pm UTC](https://community.starknet.io/t/blocking-cairozero-class-declarations/113807/1 "2024-03-25T12:15:11Z")

</div>

Greetings and salutations! Alright, let’s go 0-100. Remember [regenesis](https://www.starknet.io/en/content/starknet-regenesis-the-plan)? Well, today is the first baby step: the sequencer will no longer accept any new class declarations of CairoZero code!

Now slower.

What’s regenesis? In a nutshell, regenesis is the transition of Starknet toward safety (in the form of [Sierra](https://docs.starknet.io/documentation/architecture_and_concepts/Smart_Contracts/cairo-and-sierra/)) and away from trust and CairoZero. If you want to know more, check out [this post](https://www.starknet.io/en/content/starknet-regenesis-the-plan).

Precisely what is happening? Exactly what it says: no new CairoZero code can enter Starknet!

But what about your CairoZero contract, you say? No worries – nothing changes: the sequencer will continue to execute transactions calling your functions.

What should you 🫵🏻 do? If you’re a user – nothing! If you’re a dev – you better not be using CairoZero!

Problem? Reach out on the community forum, discord, and/or TG.

Cheerio!

---

<div class="post-metadata">

**Author:** ![web3panther.eth](https://dub1.discourse-cdn.com/flex005/user_avatar/community.starknet.io/web3panther.eth/32/84876_2.png) [@web3panther.eth](https://community.starknet.io/u/web3panther.eth)\
**Post date:** [March 27, 2024, 12:46am UTC](https://community.starknet.io/t/blocking-cairozero-class-declarations/113807/2 "2024-03-27T00:46:06Z")

</div>

Hey, this is Venkat from Hashstack. We continue to provide support for our cairo 0 code, which means we may have to send upgrades from time to time. Though we almost done with writing cairo 1 code, upgrading the protocol to this new code will need sometime. We need to ensure the upgrade doesn’t disturb state of existing loans and funds.

My suggestion is to continue supporting cairo 0 for some more time or at least allow specific accounts to declare them.

---

<div class="post-metadata">

**Author:** ![ahmetoznar](https://dub1.discourse-cdn.com/flex005/user_avatar/community.starknet.io/ahmetoznar/32/81585_2.png) [@ahmetoznar](https://community.starknet.io/u/ahmetoznar)\
**Post date:** [March 28, 2024, 1:12am UTC](https://community.starknet.io/t/blocking-cairozero-class-declarations/113807/3 "2024-03-28T01:12:53Z")

</div>

I agree with you. I believe we need to take some actions to approach regenesis, but we must ensure the safety of CairoZero contracts that are already deployed and being used by users. Therefore, I think it would make sense to at least allow certain accounts to deploy or declare CairoZero contracts.