---
schema_version: "1"
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title: What’s the Fate of Older Salesforce Customizations?
collection: admin
version: current
locale: en-us
portal_url: https://docs.salesforce.com/admin/current/en-us/service/264-0-0/pfs_enhanced_fate.md
canonical_url: https://help.salesforce.com/s/articleView?id=service.pfs_enhanced_fate.htm&release=264.0.0&type=5
source_site: help.salesforce.com
content_type: documentation
content_hash: fcc9fac9f18ece94266fce54e0b2af88a14c81457a51202635f8048a440b54f5
description: Orgs existing prior to Summer ’23 can enable Enhanced Scheduling and Optimization for all or selected service territories. Enhanced Scheduling and Optimization is backward compatible so your existing implementations remain in place after you enable it.
products:
  - Field Service
release: "264"
---
# What’s the Fate of Older Salesforce Customizations?

Orgs existing prior to Summer ’23 can enable Enhanced Scheduling and Optimization for all or selected service territories. Enhanced Scheduling and Optimization is backward compatible so your existing implementations remain in place after you enable it.

### Required Editions

<table class="slds-table slds-table_bordered slds-max-medium-table_stacked slds-m-bottom_small edition"><colgroup><col></colgroup><tbody><tr class=""><td class="slds-cell-wrap" style="vertical-align:top;">Available in: Available in Lightning Experience and Salesforce Classic in these editions where Field Service is enabled: <strong>Enterprise</strong>, <strong>Unlimited</strong>, and <strong>Developer</strong> Editions</td></tr></tbody></table>

If you’re scheduling work using Queueable Apex, use the Database.AllowsCallouts annotation for the Enhanced Scheduling and Optimization engine. If you don’t include this annotation, the request causes an exception. See [Queueable Apex: More Than an @future](https://developer.salesforce.com/blogs/developer-relations/2015/05/queueable-apex-future).

Enhanced Scheduling and Optimization uses processes and information that aren’t locally primed. A callout is used to trigger a requested service and retrieve information. If DML occurs before the callout, it causes an exception, for example, an uncommitted work pending error. To avoid an exception, ensure that DML is completed in a [separate DML transaction](https://help.salesforce.com/s/articleView?id=service.pfs_enhanced_available_limits.htm&type=5&language=en_US).