update-a-topic.md

Update a topic

A transaction that updates the properties of an existing topic. This includes the topic memo, admin key, submit key, auto renew account, and auto renew period.

Topic Properties

Field	Description
Topic ID	Update the topic ID
Admin Key	Set a new admin key that authorizes update topic and delete topic transactions.
Submit Key	Set a new submit key for a topic that authorizes sending messages to this topic.
Topic Memo	Set a new short publicly visible memo on the new topic and is stored with the topic. (100 bytes)
Auto Renew Account	Set a new auto-renew account ID for this topic (once autoRenew functionality is supported by HAPI).
Auto Renew Period	Set a new auto -enew period for this topic (once autoRenew functionality is supported by HAPI).

Transaction Signing Requirements

• If an admin key is updated, the transaction must be signed by the pre-update admin key and post-update admin key.
• If the admin key was set during the creation of the topic, the admin key must sign the transaction to update any of the topic's properties
• If no adminKey was defined during the creation of the topic, you can only extend the expirationTime.

Transaction Fees

• Please see the transaction and query fees table for base transaction fee
• Please use the Hedera fee estimator to estimate your transaction fee cost

{% tabs %} {% tab title="V1" %}

Constructor	Description
new ConsensusTopicUpdateTransaction()	Initializes the ConsensusTopicUpdateTransaction object

new ConsensusTopicUpdateTransaction()

Methods

Method	Type	Requirements
setTopicId(<topicId>)	TopicId	Required
setAdminKey(<adminKey>)	Key	Optional
setSubmitKey(<submitKey>)	Key	Optional
setExpirationTime(<expirationTime>)	Instant	Optional
setTopicMemo(<memo>)	String	Optional
setAutoRenewAccountId(<accountId>)	AccountId	Optional
setAutoRenewPeriod(<autoRenewAccountId>)	Duration	Optional
clearAdminKey()		Optional
clearSubmitKey()		Optional
clearTopicMemo()		Optional
clearAutoRenewAccountId()		Optional

{% code title="Java" %}

//Create a transaction to add a submit key
ConsensusTopicUpdateTransaction transaction = new ConsensusTopicUpdateTransaction()
    .setSubmitKey(submitKey);

//Sign the transaction with the admin key to authorize the update
ConsensusTopicUpdateTransaction signTx = transaction.build(client).sign(adminKey);

//Sign the transaction with the client operator, submit to a Hedera network, get the transaction ID
TransactionId txId = signTx.execute(client);

//Request the receipt of the transaction
TransactionReceipt receipt = txId.getReceipt(client);

//Get the transaction consensus status
Status transactionStatus = receipt.status;

System.out.println("The transaction consensus status is " +transactionStatus);

//v1.3.2

{% endcode %}

{% code title="JavaScript" %}

//Create a transaction to add a submit key
const transaction = await new ConsensusTopicUpdateTransaction()
    .setSubmitKey(submitKey)
    .build(client);

//Sign the transaction with the admin key to authorize the update
const signTx = await transaction.sign(adminKey);

//Sign the transaction with the client operator, submit to a Hedera network, get the transaction ID
const txId = await signTx.execute(client);

//Request the receipt of the transaction
const receipt = await txId.getReceipt(client);

//Get the transaction consensus status
const transactionStatus = receipt.status;

console.log("The transaction consensus status is " +transactionStatus);

//v1.4.4

{% endcode %} {% endtab %} {% endtabs %}

Get transaction values

{% tabs %} {% tab title="V2" %}

Method	Type	Requirements
getTopicId()	TopicId	Optional
getAdminKey()	Key	Optional
getSubmitKey()	Key	Optional
getTopicMemo()	String	Optional
getAutoRenewAccountId()	AccountId	Disabled
getAutoRenewPeriod()	Duration	Disabled

{% code title="Java" %}

 //Create a transaction to add a submit key
TopicUpdateTransaction transaction = new TopicUpdateTransaction()
    .setSubmitKey(submitKey);

//Get submit key
transaction.getSubmitKey()

//v2.0.0

{% endcode %}

{% code title="JavaScript" %}

 //Create a transaction to add a submit key
const transaction = new TopicUpdateTransaction()
    .setSubmitKey(submitKey);

//Get submit key
transaction.getSubmitKey()

//v2.0.0

{% endcode %}

{% code title="Go" %}

//Create the transaction
transaction := hedera.NewTopicUpdateTransaction()
    SetSubmitKey()

transaction := transaction.GetSubmitKey()

//v2.0.0

{% endcode %} {% endtab %} {% endtabs %}