---
sourceDocument: Brazil Build or modify applications
sourceDocumentLink: https://www.servicenow.com/docs/r/application-development

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    - brazil

ft:locale :

    - en-US

ft:publication_title :

    - Brazil Build or modify applications

ft:clusterId :

    - cadev

bundleId :

    - cadev

workflow :

    - Development, Data, and Analytics


---

# Customizations tracked by update sets

# Customizations tracked by update sets {#ariaid-title1}

Release version: Brazil  
Updated September 10, 2026  
![](https://www.servicenow.com/docs/portal-asset/ico-clock) 3 minutes to read
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## Summary of Customizations tracked by update sets

Update sets in ServiceNow track customizations made to application tables, fields, and records, focusing on configuration data rather than transactional task or process data.
They capture changes such as catalog item definitions and variables but exclude submitted orders or catalog tasks.
This mechanism helps with migrating and managing configuration changes across instances.
Show full answer Show less  

## Key Features

* **updatesynch attribute:** Used internally to identify tables where customizations are tracked. Customers should not add this attribute manually due to potential serious performance issues and instance instability. Core tables require special handling, and improper use can cause duplicate update records and conflicts.
* **Special handlers:** Certain elements like workflows, form sections, lists, related lists, choice lists, system dictionary entries, and field labels are grouped into single update set entries to ensure consistent updates across multiple related tables.
* **Choice lists:** Update sets store new and updated choice options separately, ensuring changes apply only to the intended tables. Avoid including large choice lists in update sets to prevent long commit times.
* **Dictionary changes:** Update sets prevent risky dictionary changes that could cause data loss, such as removing tables or changing column data types unsafely. While they track some data type changes, potentially destructive changes are skipped on the target instance with log messages to prompt manual review.
* **Home pages and content pages:** These are not included in update sets by default and must be explicitly added by unloading them. Note that homepages are deprecated on newer or upgraded instances in favor of responsive dashboards, which provide enhanced functionality and are managed separately.
* **Application-specific update sets:** Each application has its own update set containing only its associated changes, ensuring that access controls and settings are properly respected during commit operations.

## Key Outcomes

* Efficient tracking and migration of configuration changes without including transactional data.
* Protection against accidental data loss from unsafe dictionary changes during update set commits.
* Consistent handling of complex multi-table customizations through special handlers.
* Clear separation and management of application-level changes, improving access control enforcement.
* Guidance on handling deprecated features like homepages and transitioning to modern dashboards.
* Performance and stability safeguards by restricting customer use of sensitive attributes like `updatesynch`.  
Update sets track customizations to application tables, fields, and records.
Update sets capture configuration details but exclude task or process data. For example, they record catalog item definitions, variables, and variable choices, but not submitted orders or catalog tasks.

## update_synch attribute

To see the list of tables where customizations are tracked, navigate to System DefinitionDictionary and filter on attributes contains update_synch.  
Warning:  
Don't add the update_synch attribute to a dictionary record. When improperly used, this attribute can cause major performance issues or cause the instance to become unavailable. The update_synch attribute isn't accessible to customers.  
A default rule blocks the use of the update_synch attribute on a table for which it isn't predefined to avoid the following issues:

* Some core tables require special update handling because they represent information on multiple tables. When the update_synch attribute is added to these tables, duplicate update records are created, causing major conflicts that are difficult to troubleshoot and repair.
* Using the update_synch attribute to migrate data records between instances can cause performance issues. To migrate data see [Import sets key concepts](https://www.servicenow.com/docs/access?context=c_ImportSetsKeyConcepts&version=brazil&pubname=brazil-integrate-applications&ft:locale=en-US) to use an instance-to-instance import.
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## Special handlers

Special handlers represent information on multiple tables. These changes are packaged into one update set entry so that all records are properly updated when the customization is committed.

* Workflows
* Form sections
* Lists
* Related lists
* Choice lists
* System dictionary entries
* Field labels

{#customizations-tracked-update-sets__ul_qzq_32h_fr}  
Warning:  
Form sections, lists, related lists, choice lists, and field label handlers can delete and reinsert records, which may lead to unexpected results or data loss if fields reference those tables.

## Choice lists

Update sets store both new and updated choice options as separate records in the sys_update_version and sys_update_xml tables. For example, if you extend the Task table with a u_activity table, add a state field choice visible
only in your extended table.

When you publish these changes as an update set, the update only contains update and
version records for the choice you added to the u_activity table. The choice options in the
task table are unaffected.  
Warning:  
Don't use large choice lists in update sets. Doing so leads to excessively long update set commits.

## Dictionary changes

Using update sets help to prevent you from applying dictionary changes that result in data loss. For example, blocked dictionary changes include removing tables or changing a column data type.  
Update sets don't track the removal of tables from the system dictionary. You must manually remove tables from the target instance. While update sets track data type changes, the target instance skips any change that results in data loss and instead adds a log message about the action. You can use the log to make data type changes on the target instance.  
Note:  
Update set previews don't detect type mismatches when changes could cause data loss. If you delete a table column via update sets, any existing data in that column is lost when the update is committed. A warning appears noting which deletions result in data loss.

## Home pages and content pages

Home pages and content pages aren't added to update sets by default. Add pages to the current update set by unloading them.  
Important:  
The functionality found in homepages, arranging information from your instance to tell a story about your data, is found in dashboards on new instances. On upgraded instances with Next Experience enabled, users can view existing homepages if they have a direct URL, but they can't create or edit them. Responsive dashboards and Analytics Overview dashboards take over homepage functionality.{#customizations-tracked-update-sets__deprecation}

Use the [Homepage
deprecation help tool](https://www.servicenow.com/docs/access?context=homepage-deprecation-help-tool&version=brazil&pubname=brazil-now-intelligence&ft:locale=en-US) to convert the homepages on your instance to responsive dashboards.{#customizations-tracked-update-sets__deprecation-tool}  
For more information, see:

* [Dashboards in the Analytics Center](https://www.servicenow.com/docs/access?context=analytics-center-dashboards&version=brazil&pubname=brazil-now-intelligence&ft:locale=en-US).
* [Working with responsive dashboards](https://www.servicenow.com/docs/access?context=c_ResponsiveDashboards&version=brazil&pubname=brazil-now-intelligence&ft:locale=en-US).
{#customizations-tracked-update-sets__ul_plq_hjz_jrb}

## Application changes

The system creates a separate update set for each application that only contains changes associated with the application. This separation verifies that access settings for each application are properly evaluated and applied when
committing update set changes.

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