Configuration management and build traceability practices — recording what was built from which versions is standard software engineering practice.
Class B applicability added by A1:2015. Explicit requirement that integration follows a documented plan (5.1.5), not just build automation. [Class B, C]
Integration plan currency versus actual integration sequence, and build records linking integrated items to specific unit versions.
Maps to
IEC 62304: §5.6.1 Integrate software units
ISO 13485: §7.3.4 Design and development outputs
Pre-QMSR Part 820 (legacy QSR): §820.30(d) Design output.
Requirement text
The manufacturer shall integrate the software units in accordance with the integration plan (see clause 5.1.5). This requirement applies to Class B and Class C software.
Why this clause exists
Integration is not merely assembly — it is a planned, ordered process whose sequence affects what failure modes are observable and at what stage. Clause 5.6.1 requires integration to follow the integration plan rather than proceeding ad hoc because unplanned integration sequences make it impossible to attribute integration-testing failures to specific unit combinations. For software with risk control measures that depend on the correct interaction of multiple units (for example, a watchdog timer unit whose effectiveness depends on correct initialization by the main processing unit), the integration sequence must be deliberate and documented so that integration testing can verify risk controls in the correct combined-unit context.
What changed
Clause 5.6.1 was present in IEC 62304:2006. Amendment 1 (2015) added Class B applicability (the original 2006 standard required 5.6 activities for Class C only for some sub-clauses). The cross-reference to the integration plan in clause 5.1.5 is unchanged.
Common gaps (what we see in audits)
- Integration performed without a documented integration plan — Software units are combined into software items as a byproduct of the build process without a planned integration sequence. Clause 5.6.1 requires integration to be performed in accordance with an integration plan — integration that occurs implicitly during development does not meet this requirement.
- No record linking integrated software to specific unit versions — Integration records identify the integrated software item version but do not document the specific versions of the constituent software units. Without unit-version traceability, it is impossible to reproduce the integration in the event of a problem or to verify that the integration test results correspond to the released configuration.