Sitecore 10.5 is out - grab it on the [download page](https://developers.sitecore.com/downloads/Sitecore_Experience_Platform/105/Sitecore_Experience_Platform_105). Stability release: treat it as a platform dependencies update plus a refreshed editor UI. What changed below.

## TL;DR

- **Windows Server 2025** - 2022 still supported, 2019 container images gone
- **SQL Server 2025** - 2022 still supported, **2019 dropped**
- **Solr 10 only** - Solr 8 and 9 support removed, Basic Authentication mandatory
- **.NET Framework 4.8.1** - up from 4.8, Sitecore Framework libraries on .NET 10
- **Refreshed editor UI**
- **Telerik 2020.3 to 2025.2** - your own licence key needed if you compile against Telerik
- **GraphQL Playground and the Package Installer** - gone or off by default

## Dependencies

Windows Server 2025 is supported for all deployment types - SIF/SIA on-premises, Docker Compose, and AKS. Windows Server 2022 stays supported, so container images ship as `ltsc2022` and `ltsc2025`. Windows Server 2019 images are no longer shipped.

SQL Server 2025 is supported across all database roles, SQL Server 2022 remains supported, and **SQL Server 2019 is out**. Web Deploy prerequisites moved with it.

The platform itself moves from **.NET Framework 4.8 to 4.8.1** - all platform and component assemblies retargeted. Custom code compiled against 4.8 keeps working, but the runtime and an updated Visual C++ Redistributable have to be on the servers.

The Sitecore Framework libraries moved to their **.NET 10** builds, with major version jumps, so anything referencing them needs recompiling.

Always check the [compatibility table](https://support.sitecore.com/kb?id=kb_article_view&sysparm_article=KB0087164) for the exact supported versions.

## UI reskin

The editor UI moves to SitecoreAI branding - purple and grey in place of the classic XP chrome.

It is a reskin, not a redesign. Same layout, same navigation, just a more modern look.

Content Editor: flat light chrome, purple accents on the active tab and the application tabs at the bottom.

![Content Editor in Sitecore 10.5](/images/2026/12-sitecore-10-5/screens/content-editor.png)

Dialogs got the biggest visual change - rounded corners, pill buttons, purple primary action.

![Publish Item dialog in Sitecore 10.5](/images/2026/12-sitecore-10-5/screens/publish-item.png)

The reskin is not limited to Content Editor. Experience Editor gets the same treatment:

![Select a Rendering dialog in Experience Editor](/images/2026/12-sitecore-10-5/screens/insert-rendering.png)

Same for admin apps like the Control Panel and Indexing Manager:

![Indexing Manager in Sitecore 10.5](/images/2026/12-sitecore-10-5/screens/indexing-manager.png)

And Forms:

![Form builder in Sitecore 10.5](/images/2026/12-sitecore-10-5/screens/form-builder.png)

## Solr 10

Sitecore 10.4.1 ran on Solr 9.8.1. Sitecore XP 10.5 supports **Solr 10 only** - support for Solr 8 and Solr 9 has been removed. Solr 10.0.0 is the tested version, and Solr 10's **Basic Authentication is mandatory**.

Quick comparison of what Solr 10 brings:

| | Solr 9 | Solr 10 |
|---|---|---|
| Search engine | Lucene 9 | Lucene 10 |
| Java (server) | 11 minimum, tested on 11, 17, 21 | 21 minimum |
| Security | opt-in, configured by hand | Basic Authentication mandatory |
| Config | legacy `solrconfig` options still accepted | legacy options removed |

The Solr admin UI now asks for credentials.

![Solr Basic Authentication login screen](/images/2026/12-sitecore-10-5/screens/solr-auth.png)

Authentication is also the part that touches your configuration. Solr credentials now live in the connection string:

```
Sitecore_ConnectionStrings_Solr.Search: http://<user>:<password>@solr:8983/solr;solrCloud=true
```

Two more search-side changes:

- **Schema population changed.** If you customized Solr schema population, that code needs updating.
- **The managed schema file is renamed** from `managed-schema` to `managed-schema.xml`.

Known issue: pivot faceting on `SortableTextField` can return wrong results because of [SOLR-16139](https://issues.apache.org/jira/browse/SOLR-16139). Workaround is setting `ContentSearch.Solr.UseEnumFacetMethod` to `true`.

Plan a full reindex as part of the upgrade, and stand up Solr 10 fresh rather than upgrading an older cluster in place.

## Quick start with Docker

Fastest way to see 10.5 is the [containers deployment package](https://github.com/Sitecore/container-deployment/releases/tag/sxp%2F10.5.0.014188.2900). Grab it, then from the topology folder (`xp0` here):

```powershell
.\compose-init.ps1 -Topology xp0 `
    -LicenseXmlPath C:\path\to\license.xml `
    -SolrAdminPassword <admin-password> `
    -SolrConnectionPassword <connection-password>
docker compose up -d
```

`compose-init.ps1` generates certificates, hosts entries and secrets, and fills in `.env` - run it from an elevated PowerShell session. After that `https://xp0cm.localhost` is your CM.

Note the two new mandatory Solr parameters. There are no defaults, and they set up two separate accounts: `admin` for the Solr admin UI, and `sitecore` for the connection user Sitecore itself uses. Both end up in `.env` and flow into the connection strings.

Images come in `ltsc2022` and `ltsc2025` flavours - pick the one matching your host OS:

| Image | Windows Server 2022 | Windows Server 2025 |
|---|---|---|
| `sitecore-xp0-cm`, `xconnect`, workers | `10.5-ltsc2022` | `10.5-ltsc2025` |
| `sitecore-identity` | `9.0-ltsc2022` | `9.0-ltsc2025` |
| `nonproduction/solr` | `10.0.0-ltsc2022` | `10.0.0-ltsc2025` |
| `nonproduction/mssql-developer` | `2025-ltsc2022` | `2025-ltsc2025` |

Registry stays `scr.sitecore.com/sxp/`. Full tag list lives in [sitecore-tags.md](https://raw.githubusercontent.com/Sitecore/docker-images/master/tags/sitecore-tags.md). Traefik comes from Docker Hub, pinned to `v3.7.5-windowsservercore-ltsc2025` / `v3.7.5-windowsservercore-ltsc2022` in the compose file.

## Breaking changes

The [breaking changes page](https://developers.sitecore.com/downloads/Sitecore_Experience_Platform/105/Sitecore_Experience_Platform_105/Breaking_Changes) has the full list with exact type and member names. The parts worth mentioning:

### Package Installer disabled by default

`Sitecore.Packages.Disabled` now defaults to `true`, so **Package Installer and Package Designer are off**. Run the Installation Wizard on a fresh 10.5 instance and this is what you get:

![Install a Package dialog showing that Sitecore packages are disabled](/images/2026/12-sitecore-10-5/screens/package-installation-disabled.png)

Deploy `App_Config/Include/zSitecore.InstallPackage.Enable.config` to turn them back on.

### GraphQL Playground removed

Playground is out of Sitecore XP. Use Postman, Insomnia or any other GraphQL client.

### Telerik 2020.3 to 2025.2

Telerik is updated from 2020.3 to 2025.2, the NuGet package is renamed, and Telerik dependencies are removed from `Sitecore.Kernel`.

Nothing to do if you only consume Sitecore's pre-built assemblies. If your solution compiles against the Telerik NuGet packages, it now needs your own Telerik licence key - see the [breaking changes page](https://developers.sitecore.com/downloads/Sitecore_Experience_Platform/105/Sitecore_Experience_Platform_105/Breaking_Changes) for the setup.

### BinaryFormatter replacement

`BinaryFormatter` is dropped because of the known deserialization vulnerabilities. Backward compatibility is one-way: 10.5 reads data written by earlier versions, but not the other way around. Some public APIs are deprecated or behave differently as part of the replacement - check the [breaking changes page](https://developers.sitecore.com/downloads/Sitecore_Experience_Platform/105/Sitecore_Experience_Platform_105/Breaking_Changes) for the list.

### Item Service search locked down

Anonymous search access is blocked and search now enforces content security permissions by default. If you relied on the old behaviour, `Sitecore.Services.AllowSearchServiceAnonymousUser` has to be enabled explicitly.

### Computed index fields

During a parallel index rebuild, worker threads used to start with a null site context and security unconditionally disabled, so custom computed fields reading `Sitecore.Context.Site` or `SecurityDisabler.CurrentValue` indexed incorrect values. 10.5 propagates the calling thread's site context and security state into each worker, so those fields can now index different values than they did on 10.4 - details in the [breaking changes page](https://developers.sitecore.com/downloads/Sitecore_Experience_Platform/105/Sitecore_Experience_Platform_105/Breaking_Changes).

## Everything else

Plenty more in there: database upgrade scripts for Identity Server and messaging, an Application Insights connection string migration, removed legacy jQuery files, caching and rendering performance work, a serious batch of security patches, and a long list of fixes across publishing, Content Editor, Experience Editor, EXM and headless services. Full list in the [release notes](https://developers.sitecore.com/downloads/Sitecore_Experience_Platform/105/Sitecore_Experience_Platform_105/Release_Notes).

## Module compatibility

At release, **Experience Accelerator (SXA), Headless Rendering and Codeless Schema Extensions are still undergoing compatibility verification** - support lands in upcoming releases.

## Conclusion

10.5 puts XP back on current Windows, SQL, Solr and .NET, hardens security, and refreshes the editor UI.

Read the full [release notes](https://developers.sitecore.com/downloads/Sitecore_Experience_Platform/105/Sitecore_Experience_Platform_105/Release_Notes) and [breaking changes](https://developers.sitecore.com/downloads/Sitecore_Experience_Platform/105/Sitecore_Experience_Platform_105/Breaking_Changes) before planning the upgrade.