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The Apache CloudStack community uses a time-based approach to it's feature releases, with as-needed (i.e.: less formal schedule) for incremental bug-fix releases in between these feature releases. Our goal is to have a consistent schedule for new features to be merged into the master branch, along with incremental bug-fix updates between each major feature release.

Feature Release Cycle (NOTE: this section is under discussion)

Feature releases are planned for every 4 months, with a 2 month overlapping development window, giving each feature 6 months to go through it's cycle.

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Starting with our 4.0.0-incubating release, Apache CloudStack makes tried to make use of Semantic Versioning for it's its release numbering. One exception to this numbering scheme, is that the "-incubating" qualifier will be added to all release numbers until the project graduates from the Apache Incubator (this is specifically due to the rules stated in the Guide to Release Management During Incubation). Releases of CloudStack from before it's donation to the ASF did not follow Semantic VersioningIt ended out adding a fourth number and using the last three numbers in a Semantic Versioning like fashion. so in the foreseeable future ACS will have versions of the format 4.x.y.z.

For those that may not be familiar with Semantic Versioning, the number format is: X.Y.Z, where X is the major version, Y is the minor version, Z is the patch number. The community strives to ensure backward API compatibility within each major version (i.e.: code written against the CloudStack 4.0.0-incubating API should work with all future 4.y.z versions). The community may decide to increment the major version number in situations where underlying implementation details require a cloud operator to face significant challenges in upgrading from one version to the next. This should be rare situation.

In practice, feature releases will normally be an increment of the minor X version number of the project. Feature releases that break backward compatibility will cause the major version number to be incremented. Bug fix releases will never increment anything except the patch numberincrement the Y part of the version.

Security releases update the Z.

Support Lifetime of a Release

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