Summer ’26 sandboxes start upgrading around May 9. Release notes dropped April 22. If you have not looked at them yet, the window before your sandbox looks different and your customisations start behaving unexpectedly is narrow.
This is the short version of what is actually changing — not the full list of every feature, but the things admins and developers should know about before the upgrade arrives.
| Consideration | Preview Sandbox | Non-Preview Sandbox |
|---|---|---|
| When it upgrades | Early — around May 9 Upgrades ahead of production release | Later — June 5 or June 12 Stays on Spring '26 longer |
| Testing window for Summer '26 | Longer — you have weeks to validate customisations before production upgrades | Shorter — less time between sandbox and production upgrade |
| Stability during active development | Lower — your sandbox is on new code while dev work is still in progress | Higher — dev work continues on stable Spring '26 release |
| Best for orgs with | Many customisations to validate, time-sensitive compliance testing, proactive release teams | Active development sprints, tight deadlines, small teams without dedicated release bandwidth |
| How to opt in | Follow the Salesforce Sandbox Preview Guide — window closes before May 9 | No action required — non-preview is the default |
What is in Summer ’26 that admins need to know
Agentforce woven into CRM surfaces
Summer ’26 moves Agentforce from a standalone layer to something embedded in daily Sales Cloud and Service Cloud workflows. AI summaries, deal coaching suggestions, and automated research appear directly in the views reps already use. For admins, this means any customisations built against these surfaces — record detail layouts, list views, service console components — may need testing against the new Agentforce-aware UI before the upgrade lands.
Flow UI improvements: collapsible fault paths and readable data tables
Large production flows are hard to maintain when the canvas is an unnavigable tangle of fault paths and unformatted data. Summer ’26 adds collapsible fault paths and a significantly improved data table display inside Flow Builder. These are cosmetic in that they do not change flow behaviour, but the maintenance benefit is real for any org with complex automations.
Additionally, Summer ’26 extends Agentforce-powered natural language editing to Screen Flows, having added it to Record-Triggered and Scheduled Flows in Spring ’26. This remains an early-access feature and requires review before applying suggestions to production flows.
Accessibility enforcement at 200 percent zoom
Salesforce is enforcing accessibility standards for UI components at 200 percent browser zoom in Summer ’26. For orgs with custom Lightning components, custom page layouts, or Visualforce pages, this may produce unexpected layout behaviour that needs testing before the upgrade. Standard Salesforce Lightning components are already compliant. Custom-built components need to be checked.
External Client Apps migration enforcement tightens
Spring ’26 disabled new Connected App creation across all orgs. Summer ’26 tightens the enforcement further. If your org has Connected Apps that have not been migrated to External Client Apps and your integration depends on them, this is the release where that becomes an active problem rather than a pending one.
The Connected Apps that require action are the ones your org created and manages. Managed package apps from vendors are not affected.
X (Twitter) Auth Provider callback URL change
If your org uses X (formerly Twitter) as an OAuth provider for login or integration, the callback URL configuration requires manual reconfiguration in Summer ’26. This is a small but breaking change for orgs that use it — it will not fix itself automatically. Find it in Setup under Auth. Providers.
AI Content Summarizer component available in Lightning App Builder
A new AI Content Summarizer component can be dropped onto any Lightning record page directly from App Builder without writing Apex. For admins who want to surface Agentforce value to end users quickly and without a full development engagement, this is the most accessible on-ramp in the Summer ’26 release.
Have questions about anything in the Summer ’26 release notes that could affect your org? That is exactly the kind of thing our team digs into every release cycle. Reach out through truesolv.com. Follow us on LinkedIn for weekly Salesforce release breakdowns.
