1# Release Documentation 2 3## Abstract 4 5This document provides guidance to users, downstream maintainers and 6any other consumers of the Cloud Hypervisor project, this document 7describes the release process, release cadence, stability expectations and 8related topics. 9 10## Basic Terms 11 12### Stability 13 14For Cloud Hypervisor the following areas are subject to stability guarantees: 15 16- [REST API](api.md#rest-api) 17- [Command line options](api.md#command-line-interface) 18- [Device Model](device_model.md) 19- Device tree, device list, ACPI, Hyper-V enlightenments and any other 20 features exposed to guest 21- KVM compatibility 22- Rust edition compatibility 23 24This list is incomplete but this document serves as a best effort guide to stability 25across releases. 26 27### Experimental features 28 29Experimental features are under active development and no guarantees are made about their stability. 30 31List of experimental features: 32 33- TDX 34- vfio-user 35- vDPA 36 37### Security 38 39Security fixes should be included in a new point release. 40 41For security issues an advisory will be published via the GitHub security advisory process along with the release. Watching the project on GitHub will notify you of those issues. 42 43## Releases 44 45### Versioning 46 47The versioning scheme uses `MAJOR.POINT` pattern: 48 49- `MAJOR` can introduce incompatible changes along with support for new features. Changes to the [API](api.md#rest-api), 50 [CLI options](api.md#command-line-interface) and [device model](device_model.md) 51 require a notice at least 2 releases in advance for the actual change to take 52 place. 53- `POINT` contains bug fixes and/or security fixes. 54 55### Major Release Cadence 56 57Cloud Hypervisor is under active development. A new major release is issued approximately 58every 6 weeks. Point releases are issued on demand, when important bug fixes are in 59the queue. A major release would receive bug fixes for the next two cycles (~12 weeks) 60and then be considered EOL. 61 62``` 63+ - Active release support 64E - EOL 65 66 2021 2022 2023 67 | | | | | | | | | 6818.0 | | | ++++++++E 6919.0 | | | |++++++++E 7020.0 | | | | ++++++++E 7121.0 | | | | | ++++++++E 7222.0 | | | | | +++++++++E 7323.0 | | | | | | +++++++++E 74 75``` 76 77### Major Release Stability Considerations 78 79Snapshot/restore support is not compatible across `MAJOR` versions. 80Live migration support is not compatible across `MAJOR` versions. 81 82### LTS Release Cadence 83 84A regular release is promoted to LTS every 12 months. An LTS release is supported for 18 months. This gives a 6 months window for users to move to the new LTS. 85 86``` 87+ - Active release support 88E - EOL 89 90 2022 2023 2024 2025 2026 91 | | | | | | | | | | | | | | | | | 9223.0 | |+++++++++++++++++++++++++++++E 9343.0 | | | | | |+++++++++++++++++++++++++++++E 9463.0 | | | | | | | | | |+++++++++++++++++++++++++++++E 95 96``` 97 98### LTS Stability Considerations 99 100An LTS release is just a `MAJOR` release for which point releases are made for 101longer following the same rules for what can be backported to a `POINT` release. 102The focus lays on critical and security bug fixes which are pulled at the 103maintainer's discretion. 104