4.5 release notes (#2077)

Signed-off-by: Attila Mészáros <[email protected]>
Signed-off-by: Chris Laprun <[email protected]>
Co-authored-by: Chris Laprun <[email protected]>

Author: csviri

docs/_data/sidebar.yml

@@ -30,4 +30,6 @@
   - title: Migrating from v4.2 to v4.3
     url: /docs/v4-3-migration
   - title: Migrating from v4.3 to v4.4
-    url: /docs/v4-4-migration
+    url: /docs/v4-4-migration
+  - title: Migrating from v4.4 to v4.5
+    url: /docs/v4-5-migration

docs/documentation/v4-5-migration.md

@@ -0,0 +1,26 @@
+---
+title: Migrating from v4.4 to v4.5
+description: Migrating from v4.4 to v4.5
+layout: docs
+permalink: /docs/v4-5-migration
+---
+
+# Migrating from v4.4 to v4.5
+
+Version 4.5 introduces improvements related to event handling for Dependent Resources, more precisely the
+[caching and event handling](https://javaoperatorsdk.io/docs/dependent-resources#caching-and-event-handling-in-kubernetesdependentresource)
+features. As a result the Kubernetes resources managed using
+[KubernetesDependentResource](https://github.com/java-operator-sdk/java-operator-sdk/blob/73b1d8db926a24502c3a70da34f6bcac4f66b4eb/operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/event/source/informer/InformerEventSource.java#L72-L72)
+or its subclasses, will add an annotation recording the resource's version whenever JOSDK updates or creates such
+resources. This can be turned off using a
+[feature flag](https://github.com/java-operator-sdk/java-operator-sdk/blob/73b1d8db926a24502c3a70da34f6bcac4f66b4eb/operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/config/ConfigurationService.java#L375-L375)
+if causes some issues in your use case.
+
+Using this feature, JOSDK now tracks versions of cached resources. It also uses, by default, that information to prevent
+unneeded reconciliations that could occur when, depending on the timing of operations, an outdated resource would happen
+to be in the cache. This relies on the fact that versions (as recorded by the `metadata.resourceVersion` field) are
+currently implemented as monotonically increasing integers (though they should be considered as opaque and their
+interpretation discouraged). Note that, while this helps preventing unneeded reconciliations, things would eventually
+reach consistency even in the absence of this feature. Also, if this interpreting of the resource versions causes
+issues, you can turn the feature off using the
+[following feature flag](https://github.com/java-operator-sdk/java-operator-sdk/blob/73b1d8db926a24502c3a70da34f6bcac4f66b4eb/operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/config/ConfigurationService.java#L390-L390).