What’s New in Sitecore 10.4.1 – Key Improvements and Why They Matter

In case you missed it, since it was a very quiet drop, Sitecore has recently released Sitecore XP 10.4 Update-1 (10.4.1 rev. 012149) at the end of June 2025, marking the first cumulative update to the 10.4 series.

While it may appear as a routine service release, this update brings critical improvements in platform security, compatibility, deployment automation and developer experience. This was a very timely release for us, since we are in the process of a few upgrades and it addresses some key concerns which we had with components in use by the platform.

Here's a breakdown of the most important changes and why they’re worth your attention.

Key Improvements in Sitecore 10.4.1

There are 2 key improvements in this release which address some issues which was flagged up by our automated scanning tools.

Solr Upgrade to 9.8.1

The last version of Solr which was compatible in Sitecore 10.4 was Solr 8.11.2, but this became End of Life (EOL) and out of official support from the Apache Solr project on June 1, 2024. This meant no more bug fixes, security patches or updates.

With the release of 10.4.1, Sitecore officially moves to Solr 9.8.1. This change is not just about keeping up with newer capabilities - it’s essential for staying secure and supported.

There have also been some minor enhancements to the Sitecore Installation Framework (SIF) now waits for Solr to be fully available before continuing, leading to a more robust, less error-prone installations and providing better compatibility with automated DevOps pipelines

Why the update is important:

• Solr 8.11.2 is no longer maintained, posing potential security risks.
• Solr 9.x introduces performance and stability improvements.
• Addresses known security vulnerabilities in Solr 8.x, including the critical Log4j vulnerability (CVE-2021-44228)
• Required for container deployments and future Platform DXP updates.

Although a big bump in version number, the changes in the integration seem fairly minor, with very minimal changes to the configuration. We’ve not seen any significant work as a result of this change in our upgrades. We’d also highly recommend using the fully managed Solr service from SearchStax, this made the upgrade process even more pain free.

Identity Server Now on .NET 8

Sitecore Identity Server is now upgraded to run on .NET 8 (Version 8.0.16), moving away from .NET 6 which is no longer supported by Microsoft. Security is also enhanced through use of encrypted communication with SQL Server by default, which is important for protecting sensitive and private user data.

Why the update is important:

• .NET 8 offers better performance and long-term support.
• Enhanced security and compliance.
• Required encrypted communication with SQL Server enhancing security

BREAKING CHANGE: Identity Server upgrade introduces a database schema change and requires SQL encryption. Be sure to run the SQL script on the database during the upgrade.

Also note that unless you set up the encryption certificates, you will get errors during the login process. For local development, you can disable the encryption to workaround this issue. Read more in our blog here: https://konabos.com/blog/fixing-the-silent-login-fail-after-installing-sitecore-10-4-1-on-a-developer-workstation

As a side note, you may be wondering “isn’t .Net 9 the latest version, why did that upgrade to an already older version?”. You can read more about the .Net release cadence, but .Net Core is released in two flavours: Long Term Support (LTS) versions, with a 3 year support lifecycle, and Short Term Support (STS) verions, with an 18 month support lifecycle. As you can see from the timelines, .Net 8 is a LTS release and supported until a longer period that the STS version.

Coincidentally, the next LTS release is .Net 10, which scheduled for release right around the similar time that Sitecore 10.5 is slated for release. Hopefully that means the Platform DXP modules will also be using this latest version, which would be supported until November 2028.

Security Fixes and Enhancements

Several security-related improvements have been rolled into this release, covering Identity Server, Solr, and platform components. Keeping your environment secure and up-to-date should always be a priority.

This update includes a number of recent security patches such as the following, and will supersede the need to apply many of these patches:

• Security Bulletin SC2024-002-624693
• Security Bulletin SC2025-003

If you haven’t already applied these patches, the upgrade may be a better option.

Other Improvements

Application Insights Now Uses Connection Strings

The traditional Application Insights Instrumentation Key is deprecated. Sitecore now supports the Connection String model introduced by Microsoft, which helps keep your monitoring aligned with Azure best practices and comes with a lot of benefits and additional capabilities. For your older installations, you’re safe for now, the instrumentation key will continue to work for now but will no longer be receiving any updates.

EXM: Updated ChilkatDotNet48 Library

Email delivery is a key feature for EXM. This release updates the Chilkat library to the latest version, which improves reliability, security, and email deliverability. It also helps ensure EXM remains compliant with modern security protocols.

Deployment Automation Enhancements

The update includes optional scripts to automate patching, applying hotfixes and adding binding redirects, helping to simplify the installation of Sitecore XP cumulative hotfixes in the future. This should be interesting and hopefully will save time and reduce manual errors in future patch rollouts.

Resolved Issues

The update addresses multiple bugs in:

• Content Editor (UI behavior, version switching, logs)
• Experience Editor (encoding issues, crashes)
• Publishing (disappearing items, errors on remote targets)
• Headless rendering, Language fallback, Performance and NuGet packaging

Full list of improvements, breaking changes, resolved issues and known issues is available in the official release notes. Be sure to take a read so you’re aware of all the changes.

Upgrade Now

Whilst Sitecore 10.4.1 may just seem like a maintenance update, it addresses a number of key areas of the platform and delivers security, performance and improved support lifecycle across the board.

If you’re running Sitecore XP 10.4 or earlier, this update is strongly recommended not only to stay secure and supported, but to ensure a smooth path forward as Sitecore continues to evolve. If your solution has been following Sitecore best practices, then this upgrade should be relatively quick and pain-free. You’ll also want to get onto the latest Sitecore versions to take advantage of Sitecore Stream and the AI features on the Platform DXP. There’s a free tier, so take advantage now!

Need help to upgrade? Need an some expert help to review your solution and ensure it’s following best practices to help simplify future updates? Get in touch with our expert team now.