The team has been working primarily on EF Core internals, so there are no new big features in EF Core 9 (EF9) Preview 5. However, this means we really need people like you to run your code on these new internals and report back what you find. We want to fix bugs in the new internals as soon as possible in order to have a strong GA release later in the year.

That being said, there are several smaller enhancements included in preview 5. For full details, see What's new in EF Core 9. To discuss the EF9 release, go to Try EF Core 9 now! on GitHub.

Enhanced database provider for Azure Cosmos DB for NoSQL

We are working on significant updates in EF9 to the EF Core database provider for Azure Cosmos DB for NoSQL. For preview 5, these include:

• Support for hierarchical partition keys
• Use of any numeric, bool, string, or value-converted type as a partition key

See Azure Cosmos DB for NoSQL in the What's New docs for more information.

Query translation improvements

EF9 preview 5 contains three small enhancements to query translation:

• Optimization of queries using Count != 0 or Count > 0
• Translations for TimeOnly.FromDateTime and TimeOnly.FromTimeSpan

See LINQ and SQL translation in the What's New docs for more information.

Everything else in preview 5

Preview 5 contains:

• 6 enhancements
• 6 bug fixes

EF Core 9 preview 5 and Microsoft.Data.Sqlite contain work from the EF Team at Microsoft (@roji @AndriySvyryd @maumar @ajcvickers @cincuranet @SamMonoRT @luisquintanilla).