# Change to Event Emitted in Escrow.sol **URL:** \ **Category:** Developers\ **Created:** [June 9, 2022, 12:54pm UTC](https://forum.celo.org/t/change-to-event-emitted-in-escrow-sol/3784 "2022-06-09T12:54:54Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![arthurgousset](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.celo.org/arthurgousset/32/11117_2.png) [@arthurgousset](https://forum.celo.org/u/arthurgousset)\ **Post date:** [June 9, 2022, 12:54pm UTC](https://forum.celo.org/t/change-to-event-emitted-in-escrow-sol/3784/1 "2022-06-09T12:54:54Z")
Hi all 👋 [@eelanagaraj](https://github.com/eelanagaraj) and team are working on updates in [Escrow.sol](https://github.com/celo-org/celo-monorepo/blob/6b6ce69fde8f4868b54abd8dd267e5313c3ddedd/packages/protocol/contracts/identity/Escrow.sol), which we wanted to make you aware of ahead of time in case you are indexing or using its events (there is no immediate rush): TLDR: 1. add support for federated attestations ([FederatedAttestations.sol](https://github.com/celo-org/celo-monorepo/blob/ASv2/packages/protocol/contracts/identity/FederatedAttestations.sol)) 2. fix a [small existing bug](https://github.com/celo-org/celo-monorepo/pull/9617) 3. fix an inconsistency in the data emitted by the [`Withdrawal` event](https://github.com/celo-org/celo-monorepo/blob/6b6ce69fde8f4868b54abd8dd267e5313c3ddedd/packages/protocol/contracts/identity/Escrow.sol#L34) 👈 **Topic of this thread** You can find more details here: - [Change to Event Emitted in Escrow.sol · celo-org/SocialConnect · Discussion #25 · GitHub](https://github.com/celo-org/identity/discussions/25) _I copied the [message below](https://github.com/celo-org/identity/discussions/25) for ease of reference_: > # Change to Event Emitted in Escrow.sol > > Hi all 👋 > > @eelanagaraj and team are working on updates in [Escrow.sol](https://github.com/celo-org/celo-monorepo/blob/6b6ce69fde8f4868b54abd8dd267e5313c3ddedd/packages/protocol/contracts/identity/Escrow.sol) to: > > 1. add support for federated attestations ([FederatedAttestations.sol](https://github.com/celo-org/celo-monorepo/blob/ASv2/packages/protocol/contracts/identity/FederatedAttestations.sol)) > 2. fix a [small existing bug](https://github.com/celo-org/celo-monorepo/pull/9617) > 3. fix an inconsistency in the data emitted by the [`Withdrawal` event](https://github.com/celo-org/celo-monorepo/blob/6b6ce69fde8f4868b54abd8dd267e5313c3ddedd/packages/protocol/contracts/identity/Escrow.sol#L34) 👈 **Topic of this thread** > > ### Update in emitted `Withdrawal` event > > The [`Withdrawal` event](https://github.com/celo-org/celo-monorepo/blob/6b6ce69fde8f4868b54abd8dd267e5313c3ddedd/packages/protocol/contracts/identity/Escrow.sol#L34) has the following fields: > > ```solidity > event Withdrawal( > bytes32 indexed identifier, > address indexed to, // <--- to field > address indexed token, > uint256 value, > address paymentId > ); > > ``` > > and is emitted when the [function `withdraw()`](https://github.com/celo-org/celo-monorepo/blob/fe7f847667a4e3b6ef59d45106d534be26b3707f/packages/protocol/contracts/identity/Escrow.sol#L160) is called: > > ```solidity > // function withdraw() [BEFORE] > ... > emit Withdrawal( > payment.recipientIdentifier, > payment.sender, // <--- to field = payment.sender > payment.token, > payment.value, > paymentId > ); > ... > > ``` > > Notice that the `to` field is set to the `payment.sender` instead of the `msg.sender` who will actually receive the withdrawal. > We would like to update the data emitted in this event to be `msg.sender.`: > > ```solidity > // function withdraw() [AFTER] > ... > emit Withdrawal( > payment.recipientIdentifier, > msg.sender, // <--- to field = msg.sender > payment.token, > payment.value, > paymentId > ); > ... > > ``` > > ### What does this mean? > > This change would be a PATCH upgrade, according to our [Core Contracts versioning process](https://docs.celo.org/community/release-process/smart-contracts#versioning), because it is: > > - backwards compatible, and > - doesn’t change the ABI. > > ⚠ But (!), this change would modify the **data captured by applications** that index the Escrow.sol events emitted on-chain. From the moment the contract is upgraded, the `to` field would reflect `msg.sender` instead of `payment.sender`. > > ### 🙌 Call to action​:point\_down: > > Please comment below if you are indexing Escrow.sol events and might be affected by this change. > > We would like to share this update ahead of time so (d)apps that use the contract or index its events can prepare accordingly. > > Thanks! ---
**Author:** ![DonaFlorinda](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.celo.org/donaflorinda/32/7416_2.png) [@DonaFlorinda](https://forum.celo.org/u/DonaFlorinda)\ **Post date:** [August 9, 2022, 10:10pm UTC](https://forum.celo.org/t/change-to-event-emitted-in-escrow-sol/3784/2 "2022-08-09T22:10:26Z")
nice! thx. naive question; could we store events in the blockchain for free or it costs gas, since it is a call? figuring out solidity. ---
**Author:** ![DonaFlorinda](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.celo.org/donaflorinda/32/7416_2.png) [@DonaFlorinda](https://forum.celo.org/u/DonaFlorinda)\ **Post date:** [August 11, 2022, 3:04pm UTC](https://forum.celo.org/t/change-to-event-emitted-in-escrow-sol/3784/3 "2022-08-11T15:04:28Z")
answering myself, and maybe others, > Logs were designed to be a form of storage that costs significantly less gas than contract storage. Logs basically cost 8 gas per byte, whereas contract storage costs 20,000 gas per 32 bytes. ---
**Author:** ![arthurgousset](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.celo.org/arthurgousset/32/11117_2.png) [@arthurgousset](https://forum.celo.org/u/arthurgousset)\ **Post date:** [August 12, 2022, 12:35pm UTC](https://forum.celo.org/t/change-to-event-emitted-in-escrow-sol/3784/4 "2022-08-12T12:35:46Z")
Thanks for following up here @DonaFlorinda!