chore(main): release 0.20.0

Author: cachekit-release-bot[bot]

.release-please-manifest.json

@@ -1,3 +1,3 @@
 {
-  ".": "0.19.0"
+  ".": "0.20.0"
 }

CHANGELOG.md

@@ -1,5 +1,26 @@
 # Changelog
 
+## [0.20.0](https://github.com/cachekit-io/cachekit-py/compare/v0.19.0...v0.20.0) (2026-09-25)
+
+
+### ⚠ BREAKING CHANGES
+
+* **config:** CachekitConfig drops retry_on_timeout, max_retries, retry_delay_ms, early_refresh_ratio, enable_corruption_detection and max_key_size, and no longer reads CACHEKIT_RETRY_ON_TIMEOUT, CACHEKIT_MAX_RETRIES, CACHEKIT_RETRY_DELAY_MS, CACHEKIT_EARLY_REFRESH_RATIO, CACHEKIT_ENABLE_CORRUPTION_DETECTION or CACHEKIT_MAX_KEY_SIZE. None of them changed behaviour. Passing one to CachekitConfig(...) now raises ValidationError; CachekitConfig ignores a still-exported env var, so startup is unaffected. CachekitIOBackendConfig declares its own max_retries under the same prefix and still parses CACHEKIT_MAX_RETRIES; this release does not change it. Integrity checking is set per decorator (integrity_checking=), refresh-ahead timing by L1CacheConfig.swr_threshold_ratio, and Memcached retries by MemcachedBackendConfig.retry_attempts.
+* **decorators:** `CachekitIOBackend(...)` configuration errors (missing, empty or whitespace-containing API key; invalid API URL) now raise `cachekit.config.ConfigurationError` at construction instead of `ValueError` or pydantic `ValidationError`, so code catching `ValueError` there must catch `ConfigurationError`. `@cache.io(backend=...)` and `@cache.io(config=...)` now raise `ConfigurationError` instead of silently ignoring the argument. Under `set_default_backend()`, `@cache(config=...)` now uses the backend inside `config=` instead of the module default. `cachekit.backends.cachekitio.client.get_sync_http_client()` is replaced by `lease_sync_http_client()`, which returns a `SyncClientLease`: hold the lease for as long as its `.client` is used, because the client is closed when the lease is dropped.
+* **encryption:** single-tenant tenant_id defaults to "default", not a deployment UUID (LAB-4666) ([#321](https://github.com/cachekit-io/cachekit-py/issues/321))
+
+### Bug Fixes
+
+* **cache_handler:** evict on corrupt CK frame header, not just payload (LAB-4075) ([#307](https://github.com/cachekit-io/cachekit-py/issues/307)) ([ed799c1](https://github.com/cachekit-io/cachekit-py/commit/ed799c133db435a39e87d363474bd23f5ff5624a))
+* **decorators:** [@cache](https://github.com/cache).io accepts api_key= and rejects backend= (LAB-4643) ([#320](https://github.com/cachekit-io/cachekit-py/issues/320)) ([4d36167](https://github.com/cachekit-io/cachekit-py/commit/4d3616759cdf491ef46f9e103b47fa043e217d18))
+* **encryption:** single-tenant tenant_id defaults to "default", not a deployment UUID (LAB-4666) ([#321](https://github.com/cachekit-io/cachekit-py/issues/321)) ([c5da48a](https://github.com/cachekit-io/cachekit-py/commit/c5da48a702840698546bcc1e369c1c475c7dcfa2))
+* **redis:** release a lock won after acquire_lock cancellation (LAB-3606) ([#293](https://github.com/cachekit-io/cachekit-py/issues/293)) ([4cfdc63](https://github.com/cachekit-io/cachekit-py/commit/4cfdc63a67991f117d75275feb57912ab861b4b7))
+
+
+### Code Refactoring
+
+* **config:** remove six CachekitConfig knobs nothing reads (LAB-4740) ([#324](https://github.com/cachekit-io/cachekit-py/issues/324)) ([27e1f95](https://github.com/cachekit-io/cachekit-py/commit/27e1f95dc727e1b2c03ebed8c4dfd42f7caa1ad2))
+
 ## [0.19.0](https://github.com/cachekit-io/cachekit-py/compare/v0.18.0...v0.19.0) (2026-09-22)
 
 

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "maturin"
 
 [project]
 name = "cachekit"
-version = "0.19.0"
+version = "0.20.0"
 description = "Backend-agnostic caching for Python — intent-based decorators with circuit breaker, distributed locking, Prometheus metrics, and optional zero-knowledge AES-256-GCM encryption, on a Rust-powered core. Zero-config L1 in-memory; scales to Redis, Memcached, File, or CachekitIO."
 readme = "README.md"
 license = {text = "MIT"}

rust/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cachekit-rs"
-version = "0.19.0"
+version = "0.20.0"
 edition = "2021"
 authors = ["cachekit Contributors"]
 description = "High-performance storage engine for caching with compression and encryption"

src/cachekit/__init__.py

@@ -68,7 +68,7 @@ def custom_function():
     ```
 """
 
-__version__ = "0.19.0"
+__version__ = "0.20.0"
 
 from collections.abc import Callable
 from typing import Any, TypeVar