How to Upgrade Your Sitecore XP or XM Codebase: A Step-by-Step Guide

In today’s ever-evolving digital world, staying current with your Sitecore XM/XP platform is crucial for optimal performance, security, and user satisfaction. This article provides a comprehensive roadmap for executing a successful Sitecore XP code upgrade, covering everything from .NET and package updates to configuration management, content synchronization, and security hardening.

1. Code Upgrade: Core Actions

Key Steps

Upgrade .NET & Sitecore Versions

1. Align your solution with the latest .NET LTS and the Sitecore version you’re targeting.*
2. Review compatibility of custom modules and third-party code. Upgrade or update as needed. *

Update Sitecore Assemblies & Packages

1. Refer to the assembly list file for official Sitecore references. *
2. Remove packages.config files; create a packages.props for centralized package references management. *

Hotfixes

1. Remove any obsolete hotfix DLLs or config patches. Check each hotfix ID online or in release notes to confirm if it’s included in newer versions.
2. Install latest Cumulative Hotfix to keep solution secured and up to date. *

Config File Management

1. Use env:require and role:require for environment-/role-specific configurations instead of build configuration transformations where possible.*
2. Search for environment URLs that need updating.

Replace Deprecated API Calls

1. xConnect client API updates when coming from Sitecore 9.  
2. Fast Queries (unsupported past Sitecore 10.1) should be converted to Solr Content Search or another recommended approach. *

NuGet Updates 

1. Use the Sitecore Solution Upgrade Tool when possible, but be prepared for manual fixes. *

Handle Build Errors Systematically

1. If extensive changes are required, temporarily comment out the broken code with a //TODO: Upgrade tag to revisit later.

Review Custom Logging

1. If moving to Azure, consider Application Insights or other cloud-friendly logging approaches.

Resiliency Checks

1. Ensure code gracefully handles intermittent Solr or xDB failures.
2. Confirm the build artifact for Sitecore Solution and xConnect does not include unnecessary or duplicate Sitecore assemblies. Exclude Sitecore assemblies based on solution used (TDS, HPP or other) *
3. Sanitize solution and check for potential memory leaks like unclosed Streams etc.
4. Check for Core database calls from CD server (Security database should be enough for CD servers).
5. Check for potential Master database calls from CD server. *

2. Configuration Updates

Web Config & Transforms

1. Merge the new Sitecore stock web.config changes into your existing config. *
2. Adjust environment-specific transforms (e.g., web.debug.config, web.config.xdt). *
3. Validate behavior in Local, UAT, and Production.

Logging

1. Compare your logging approach with Sitecore’s recommended practices in the new version.
2. If on Azure, refine or add Application Insights.
3. Ensure no unhandled exceptions or unexplained errors appear in logs post-upgrade.
4. Ensure appropriate logging trace level is used and no unnecessary bloating occurs to minimize Application Insights noise and cost i.e. “Warn” for Search.log. *

Authentication

1. Confirm SSO endpoints (e.g., Identity Server, Azure AD) remain correct.
2. Disable any unused identity configs if SSO is not in use.
3. Thoroughly test login flows.

App_Config Customizations & Supporting Files

1. Audit App_Config\Environment patches for updated domain references.
2. Check module compatibility (e.g., Sidekick, SmartSolrSchema). *
3. Validate Solr endpoints and performance settings (e.g., max query limits). *
4. If using Azure staging slots, confirm special configs (e.g., disabled tasks/jobs) remain correct. *

3. Hotfixes*

Check All References

• Verify PackageReference entries for any Sitecore hotfixes.

Update or Remove

• Install the latest matching hotfix remove it if no longer needed.

Avoid Major Issues

• Outdated hotfixes in xConnect can create severe compatibility problems and may require a restore from backups.

4. Custom Facets and Analytics

1. Identify Existing Facets
   1. Ensure compatibility with upgraded Sitecore XP and xConnect versions.
2. Update xConnect Deployment
   1. Re-package and redeploy facet code if necessary.
3. Synchronize Models
   1. Regenerate or update xConnect models to ensure custom facets remain mapped correctly.
4. Test Data Flow
   1. Validate interactions, contacts, and analytics reporting post-upgrade.
5. Reference Official Guides
   1. For deeper instructions, search “Sitecore xConnect custom facets deployment guide” in Sitecore documentation.

5. Security Hardening & Headers

Security Guide

• Follow the official Sitecore Security Guide for Sitecore XP to implement recommended hardening steps.
• Migrate users to Security Database to detach Identity/Membership tables from Core database.

Security Headers *

• Configure: X-Content-Type-Options, X-XSS-Protection, Content-Security-Policy, etc.
• Test: Use securityheaders.com to validate and score your headers.
• Ongoing Maintenance: Include in onboarding and provisioning processes for each environment.
• Content Security Policy (CSP) Note: Particularly tricky for headless apps and solutions with a lot of external integrations — ensure you whitelist required external scripts, fonts, images, and other assets.

6. Front-End Apps

Node.js Compatibility

• Review Current Version
  • Upgrade to the latest LTS for better security and performance.
• Check Dependencies
  • Use npm outdated or yarn outdated and address major version bumps or deprecations.
• Validate Builds
  • Rebuild locally, watch for errors or regressions, and run automated tests.

Updating the Sitecore JSS SDK and Sitecore Headless Services module

1. Check Compatibility
   1. Align your JSS version with the Sitecore upgrade.
2. Upgrade the JSS Packages
   1. Update @sitecore-jss/* dependencies to recommended versions.
3. Validate Configuration
   1. Ensure layout service endpoints, API keys, and environment variables are correct.
4. Check for Breaking Changes
   1. Review JSS release notes for deprecated APIs or structure changes.
5. Rebuild & Smoke Test
   1. Confirm everything (including Experience Editor) works as expected.
6. Confirm SSR/ISR
   1. For Next.js or similar frameworks, ensure server-side rendering or incremental static regeneration remains valid.

7. Smoke Testing

• Local Verification
  • Confirm site pages load correctly and Experience Editor works if it was functional pre-upgrade.
• Customer Test Plan
  • If available, use a formal test plan to validate advanced scenarios or custom features.

8. Content Upgrade

1. TDS/Unicorn/SCS Sync
   1. Sync customizations to source control before upgrading.
   2. Update or install and configure Sitecore CLI.
2. Database Upgrades
   1. Upgrade Core, Security, Master, and Web databases following the official Sitecore guide.
3. UpdateApp Tool
   1. Choose the correct package for your “from” and “to” versions (e.g., 8.2.x XP → 10.x XM).
4. Attach Databases to New Environment
   1. Start Sitecore on the new environment to finalize the upgrade.
5. Install Sitecore PowerShell Extensions (SPE)
   1. Ensure compatibility with your new Sitecore version (and SXA if in use).
6. Re-sync Items
   1. Restore custom system items if needed.
7. Check Roles & Users
   1. Migrate all relevant roles and users.
   2. If using Entra/Okta ensure no users created and virtual users used instead.
8. IAR Files
   1. Confirm “Item as Resources” (.dat) files restore system items automatically if removed.
   2. Ensure and correct xConnect rules that might still point to deprecated assemblies. Run IAR Sitecore PowerShell report to find faulty items.

8.1 Content Item Changes During the Upgrade 

Content Hygiene

• If the Master database is in poor shape (publishing triggers discrepancies), address issues early and work with content authors for cleanup.

9. Miscellaneous Tips

SXA

• Trigger SXA content upgrade by adjusting the version at /sitecore/system/Settings/Foundation/Experience Accelerator/Upgrade/Current.

Sitecore Forms

• Reset forms to standard values if needed.
• Correct JQuery versions on form items where necessary.  

Sitecore Instance Name

• Keep CD server instance names blank to ensure publishing applies to all CDs.

Build Configurations

• Remove outdated configs (e.g., “Live”) in bulk via PowerShell in VS:
  • powershell
  • CopyEdit
  • Get-Project -All | Foreach { $_.ConfigurationManager.DeleteConfigurationRow("Live") }

Source Code Repo Conventions 

• refer NuGet packages over checking in DLLs.
• Consider linting/code analysers if time permits.

Timezone

• Ensure correct time zone is used in Sitecore settings. 

10. Content Synchronization Timing

Two Major Sync Points:

• Pre-UAT Testing
• Pre-Go-Live (after a content freeze)

Scope: Migrate content and media, and reapply any manual changes recorded during the upgrade.

Tools: Sitecore Sidekick can help; ensure matching versions if you’re also using Unicorn.

Conclusion

A successful Sitecore XP or XM upgrade demands more than just updated files—it requires careful planning, thorough testing, and detailed documentation. From removing old hotfixes and validating transforms to final content synchronization and security checks, each step in the process helps ensure a stable, high-performing Sitecore environment that meets evolving business needs.

Pro Tip: Always refer to Sitecore’s official documentation or community knowledge bases for specialized scenarios (e.g., xConnect, SXA, or custom analytics). With a meticulous upgrade plan, your Sitecore platform can continue to deliver exceptional digital experiences.

Are you ready to talk about your roadmap?

Get in touch with our team today! 

* Included in Dataweavers' Fusion Automatic Upgrade and Verify tools and Platform Standards, ensuring streamlined Sitecore upgrade and ongoing management.