A company is creating a new feature for existing software.

A canary deployment best matches the requirement to test a new feature with a small group of users while the current version remains deployed for everyone else. In a canary approach, a new application revision is released to a limited portion of traffic/users first . This allows the team to collect real user feedback and validate behavior under production-like conditions without exposing the full user base to risk.

AWS deployment guidance for progressive delivery aligns with this concept: you start by directing a small percentage of requests to the new version, monitor results (such as error rates, latency, and business outcomes), and keep the stable version handling the majority of traffic during the evaluation period. This directly satisfies the requirement that the “current software version remains deployed” while testing occurs.

Once the feature is validated, the canary strategy supports promoting the new revision to the remaining population by shifting traffic from the old version to the new version—commonly ending with a transition to 100% of users on the new version. This satisfies the requirement to deploy to “all other users at the same time” after the small-group validation step is complete.

Why the other options are less suitable:

All-at-once exposes all users immediately, so there is no limited-user validation phase.

In-place replaces the existing version on the same infrastructure, typically without maintaining a parallel stable path for a subset of users.

Linear gradually shifts traffic in fixed increments over time, rather than validating with a small group and then moving the remainder in one step.