Microsoft released .NET 10 in November 2025 as a long-term-support release. For an established product, the interesting work begins after the first successful build: proving that deployment and recovery are understood.
Rehearse with realistic configuration
Run the candidate in an environment that exercises the real hosting model, identity provider and external integration contracts. Synthetic data is appropriate, but it should include awkward cases such as large records, expired credentials and partially completed workflows.
Check startup, health endpoints, background jobs and graceful shutdown. An application that serves requests correctly can still lose work when a deployment terminates a worker at the wrong moment.
Make rollback a procedure
Write the exact steps to restore the previous application version. Identify configuration changes and database migrations that affect compatibility. If a schema change cannot be rolled back safely, use a staged migration that allows both application versions during the transition.
Decide what evidence will halt a rollout: increased error rate, failed business operations or a sustained latency change. Choose thresholds from the service’s operating requirements rather than an arbitrary percentage.
The rehearsal should produce a usable runbook and a list of unresolved risks. That is a stronger outcome than a ticket saying only that the application compiles on the new runtime.