Added description of the grace period

docs/administration/configuration/repository_configuration.md

@@ -198,6 +198,26 @@ This limit is enforced on publishing a new version and only covers archived vers
     In Legacy storage engine you can see performance degradation if you store too many versions.
     The default value of 5 is the recommended value, but the less content you have overall, the more you can increase this to, for instance, 25 or even 50.
 
+### Grace period for archived versions
+
+After a new version of a content is published, for a period of time the previous version (now archived) can still be loaded using the same permission set as the published version.
+
+This period is called the grace period and it prevents race conditions that can occur when a new version is published at the same time as someone is accessing the content item.
+
+The duration can be configured using the `grace_period_in_seconds` setting.
+After a version has been archived for longer than specified in the configuration, the grace period ends and the version is treated the same as all the other archived versions, including the need of [`content/versionread` policy](policies.md#content) to access it.
+
+``` yaml
+ibexa:
+    repositories:
+        default:
+            options:
+                grace_period_in_seconds: 30
+```
+
+`grace_period_in_seconds` uses the [PHP's `max_execution_time`](https://www.php.net/manual/en/info.configuration.php#ini.max-execution-time) value by default.
+Set the value to 0 do disable grace period for archived versions.
+
 ### Removing versions on publication
 
 With `remove_archived_versions_on_publish` setting, you can control whether versions that exceed the limit are deleted when you publish a new version.