Ontario Subscription HL7® FHIR® Implementation Guide v1.0.0
This implementation guide provides guidance for organizations using FHIR R4 to leverage the enhanced Publish/Subscribe (Pub/Sub) capabilities introduced in FHIR R5. By utilizing the R5 Subscription Backport Implementation Guide, you can adopt the more robust and feature-rich R5 Pub/Sub model without requiring a full upgrade to R5.
Scope
The scope of the subscription implementation guide (IG) is to provide comprehensive guidance on leveraging the advanced Publish/Subscribe (Pub/Sub) capabilities of FHIR R5 within an existing FHIR R4 infrastructure. Specifically, the IG will focus on the use of the R5 Subscription Backport to enable healthcare organizations, solution vendors, and system integrators in Ontario to implement real-time, event-driven data exchange notifications using FHIR. This approach allows for the adoption of key R5 features, such as SubscriptionTopic and SubscriptionStatus resources, enhanced filtering, and standardized notification bundles, without requiring a full migration to R5.
Status
This implementation guide has gone through a formal governance committee review and approval process resulting in a balloted draft status.
FHIR is an evolving trial-for-use standard, so additional changes by HL7 are expected. We will continue to monitor developments and assess any potential impacts and publish updates as they emerge.
*SIMPLIFIER.NET is a web-based FHIR registry built by Firely that serves as the hosting platform for the Canadian FHIR Registry sponsored by Canada Health Infoway.
Status
November 27, 2025
Version 1.0.0 approved by Digital Health Interoperability Standards Committee and is available for public access