> _Originally released on 2019-11-13 14:07:04+00:00 ([link](https://github.com/zalando-incubator/kopf/releases/tag/0.23rc1))._
**TL;DR:** Massive refactoring, renames, code moves. Generally, should be backward-compatible.
RISKY CHANGES (can be BREAKING, should be not):
* Authentication and API talking are fully reworked: `pykube-ng` and `kubernetes` clients are now piggybacked by default to extract the endpoints and credentials, but are not used for the API communication. This can break API connectivity in some cases. 226 227
* In-memory containers introduced to carry the technical information/objects/flags for individual resources. This can lead to increased memory usage in huge clusters with _thousands_ of monitored resources. 230
* `kopf.on.resume()` handlers were fixed, and can now execute when previously they were not executed by mistake, but this could be taken as an expected behaviour. This can lead to massive patches of all objects on every operator startup. 230
* Massive internal renames and code moves; not exposed publicly, unless hacks or monkey-patching were used. 209 210 211
* `cause.event` is renamed to `cause.reason` to avoid terminology conflicts. 201
New features:
* `kopf.on.startup()` handlers for operator initialisation. 225
* `kopf.on.cleanup()` handlers for operator shutdown. 225
* `kopf.on.login()` custom authentication handlers. 226
* `kopf.on.probe()` handlers for liveness metrics. 226
* Pod's liveness probes with `kopf run --liveness`. 228
* Explicit owner is not needed in `kopf.adopt()` and hierarchy methods, current object is used by default. 203
* `retries=` limiter for handlers in addition to `timeout=`. 222
* `errors=TEMPORARY`, `errors=PERMANENT`, `errors=IGNORED` modes for handlers. 222
Bugfixes:
* `kopf.on.resume()` handlers are not repeated every few minutes for no reason. 229 230
* `kopf.on.resume()` are executed if they go after the on-create/on-update handlers. 230
* `kopf.on.resume()` can be retried in case of temporary or arbitrary errors. 230
* `kopf.on.resume()` can have sub-handlers. 230
* There can be 2+ of the`kopf.on.resume()` handlers. 230
* `spec`, `status`, `metadata` fields are not added to the body when absent. 198
* Ignore asyncio signal handlers on Windows. 220
Internal changes:
* Fully type-annotated in the code (not in the tests). 195 196 197 200 201
* Fully asynchronous internally (asyncio/aiohttp); synchronous pykube-ng client is removed. 217 227
* Handler outcomes and persistent state management separated from each other. 221
* E2E tests are now isolated from each other, preventing false-positives. 205
* The latest k8s & minikube versions are used in e2e tests. 193