Glossary · Automation software engineering and architecture
Major version
Also known as: Major release number
German: Hauptversion
In software versioning, the major version is the first number of a version identifier such as 3.1.4; under semantic versioning it is incremented when a release makes changes that are incompatible with the previous public interface.
- Software engineering
In one sentence
The major version is the first number of a version identifier; semantic versioning raises it for incompatible interface changes.
Example
The drive library moves from version 2.7.0 to 3.0.0 because a function block parameter was renamed, so existing PLC projects must be adapted before they can use it.
How it applies
- Engineering: A new major version signals a Breaking change: interfaces, data formats or behavior changed so that dependent projects may no longer build or behave the same. Teams plan migration work before adopting it.
- Maintenance: Plants often keep a machine on an older major version for years. Vendors state how long an older major version receives fixes, which matters for Patch management.
- Documentation: A major version usually needs a migration section in the Release note and a review of every manual chapter that describes the changed interface. Documentation teams often version their manuals by major version.
Major version vs. minor version
A Minor version adds functionality in a backward-compatible way; a major version may remove or change existing behavior. The meaning only holds if the project actually follows Semantic versioning; many industrial products use their own numbering schemes, so check the vendor's versioning policy.