# Upgrade Proposal for a Forked Network

**URL:** https://forum.openzeppelin.com/t/upgrade-proposal-for-a-forked-network/42449
**Category:** Defender
**Created:** [December 4, 2024, 8:08pm UTC](https://forum.openzeppelin.com/t/upgrade-proposal-for-a-forked-network/42449 "2024-12-04T20:08:07Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![Andrew\_Mazzola](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.openzeppelin.com/andrew_mazzola/32/21916_2.png) [@Andrew\_Mazzola](https://forum.openzeppelin.com/u/Andrew_Mazzola)
#### Post date: [December 4, 2024, 8:08pm UTC](https://forum.openzeppelin.com/t/upgrade-proposal-for-a-forked-network/42449/1 "2024-12-04T20:08:07Z")

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I am trying to test an upgrade proposal on a MainnetFork network. I have created this Fork using Tenderly. I submitted the proposal to Defender, but now I am unsure how to 'accept' the proposal in such a way that it will be applied to the fork and not actual mainnet.

I tried adding the fork network in the defender settings, but i get this error

" there is already a public network with chain id 0x1 " with makes no sense to me . Obviously yes i know that. Its a fork network.

How can i accompliish my ultimate goal of applying the OZ defender proposal to the fork network ?