Add version text for Gitaly Cluster changes

doc/administration/gitaly/praefect.md

@@ -983,18 +983,12 @@ cluster.
 > - Introduced in GitLab 13.1 in [beta](https://about.gitlab.com/handbook/product/gitlab-the-product/#alpha-beta-ga) with feature flag `gitaly_distributed_reads` set to disabled.
 > - [Made generally available and enabled by default](https://gitlab.com/gitlab-org/gitaly/-/issues/2951) in GitLab 13.3.
 > - [Disabled by default](https://gitlab.com/gitlab-org/gitaly/-/issues/3178) in GitLab 13.5.
+> - [Enabled by default](https://gitlab.com/gitlab-org/gitaly/-/issues/3334) in GitLab 13.8.
 
 Praefect supports distribution of read operations across Gitaly nodes that are
 configured for the virtual node.
 
-The feature is disabled by default. To enable distributed reads, the `gitaly_distributed_reads`
-[feature flag](../feature_flags.md) must be enabled in a Ruby console:
-
-```ruby
-Feature.enable(:gitaly_distributed_reads)
-```
-
-If enabled, all RPCs marked with `ACCESSOR` option like
+All RPCs marked with `ACCESSOR` option like
 [GetBlob](https://gitlab.com/gitlab-org/gitaly/-/blob/v12.10.6/proto/blob.proto#L16)
 are redirected to an up to date and healthy Gitaly node.