Versioning

How Sentinel versions work, mapping between release and crate versions, and changelogs.

Note: You are viewing documentation for release 25.12. See the latest documentation for the current release.

Dual Versioning Scheme

Sentinel uses two versioning systems for different purposes:

System	Format	Example	Used For
Release Version	CalVer (`YY.MM`)	`25.12`	Documentation, downloads, public announcements
Crate Version	SemVer (`MAJOR.MINOR.PATCH`)	`0.2.0`	Cargo.toml, crates.io, dependency management

Release Version (CalVer)

Public-facing releases use Calendar Versioning in YY.MM format:

25.12 = December 2025
25.11 = November 2025

This provides:

Clear indication of release age
No implied stability promises beyond the release notes
Simple chronological ordering

Crate Version (SemVer)

Rust crates published to crates.io use Semantic Versioning:

MAJOR.MINOR.PATCH

0.1.0  - Initial development
0.2.0  - New features (pre-1.0, may have breaking changes)
1.0.0  - First stable release
1.1.0  - New features, backwards compatible
1.1.1  - Bug fixes only
2.0.0  - Breaking changes

Version Mapping

This table maps public release versions to their corresponding crate versions:

Release	Crate Version	Protocol	Release Date	Status
25.12	`0.2.0`	`0.1.0`	2025-12-15	This version
—	`0.1.0`	`0.1.0`	2025-11-01	Internal

Finding Your Version

From the binary:

sentinel --version
# sentinel 0.2.0 (release 25.12)

From Cargo.toml:

[dependencies]
sentinel = "0.2"
sentinel-agent-protocol = "0.1"

From the documentation URL:

/docs/ — Current release
/docs/v/25.12/ — This release

Changelog

Release 25.12

Crate version: 0.2.0 Protocol version: 0.1.0 Release date: December 2025

Added

Core Proxy
- HTTP/1.1 and HTTP/2 support
- HTTPS with TLS 1.2/1.3
- Configurable listeners (multiple ports, protocols)
- Request/response header manipulation
Routing
- Path-based routing with prefix, exact, and regex matching
- Host-based virtual hosting
- Method-based routing
- Header-based routing conditions
Upstreams
- Multiple backend targets with load balancing
- Round-robin and random load balancing strategies
- Active health checks (HTTP, TCP)
- Passive health monitoring with circuit breaker
- Connection pooling
Agent System
- Unix socket transport for local agents
- gRPC transport for remote agents
- Request/response lifecycle hooks
- WebSocket frame inspection hooks
- Fail-open mode for agent failures
- Agent timeout configuration
Observability
- Prometheus metrics endpoint
- Structured JSON logging
- Request tracing with correlation IDs
- OpenTelemetry integration
Configuration
- KDL configuration format
- Environment variable substitution
- Configuration validation
- Hot reload via SIGHUP

Compatibility Matrix

Agent Compatibility

Sentinel Release	Protocol	Compatible Agent Versions
25.12	`0.1.0`	Agents built with protocol `0.1.x`

Rust Toolchain

Sentinel Release	Minimum Rust Version	Recommended
25.12	1.70.0	1.75.0+

Release Schedule

Sentinel follows a monthly release cadence:

Feature releases: First week of each month
Patch releases: As needed for security or critical bugs

Version Support

Release	Status	Security Fixes Until
25.12	Previous	26.03 (3 months)