More changes from review

Some rewordings

Author: peachdawnleach

src/current/v25.3/upgrade-with-pcr.md

@@ -5,10 +5,10 @@ toc: true
 docs_area: manage
 ---
 
-When [**physical cluster replication (PCR)**]({% link {{ page.version.version }}/physical-cluster-replication-overview.md %}) is enabled, you must use the process on this page to upgrade your clusters. This process ensures that the standby cluster upgrades before the primary cluster.
+When [**physical cluster replication (PCR)**]({% link {{ page.version.version }}/physical-cluster-replication-overview.md %}) is enabled, you must use the process on this page to upgrade your clusters. This process ensures that the standby cluster safely upgrades before the primary cluster, preventing any version incompatibility.
 
 {{site.data.alerts.callout_info}}
-The entire standby cluster must be on the same version as the primary cluster or a version the primary cluster can directly upgrade to. Within the primary and standby CockroachDB clusters, the _system virtual cluster (SystemVC)_ must be at a cluster version greater than or equal to the _app virtual cluster (AppVC)_.
+The entire standby cluster must be on the same major version as the primary cluster or a major version the primary cluster [can directly upgrade to]({% link {{ page.version.version }}/upgrade-cockroach-version.md %}#compatible-versions). Within the primary and standby CockroachDB clusters, the _system virtual cluster (SystemVC)_ must be at a cluster major version greater than or equal to the _app virtual cluster (AppVC)_.
 {{site.data.alerts.end}}
 
 ## Upgrade primary and standby clusters
@@ -25,14 +25,12 @@ To upgrade your primary and standby clusters:
     If you need to [roll back]({% link {{ page.version.version }}/upgrade-cockroach-version.md %}#roll-back-a-major-version-upgrade) an upgrade, you must do so before the upgrade has been finalized.
     {{site.data.alerts.end}}
 
-    After you have finalized the upgrade on the standby cluster's SystemVC, the clusters can remain in this state for an indefinite amount of time. You can wait to upgrade the primary cluster as long as is needed.
-
 1. [Upgrade the binaries]({% link {{ page.version.version }}/upgrade-cockroach-version.md %}#perform-a-major-version-upgrade) on the primary cluster. Replace the binary on each node of the cluster and restart the node.
 
 1. [Finalize]({% link {{ page.version.version }}/upgrade-cockroach-version.md %}#finalize-a-major-version-upgrade-manually) the upgrade on the primary cluster's SystemVC. 
 
     {{site.data.alerts.callout_info}}
-    If you need to [roll back]({% link {{ page.version.version }}/upgrade-cockroach-version.md %}#roll-back-a-major-version-upgrade) an upgrade, you must do so before the upgrade has been finalized. Rolling back the upgrade on the primary cluster does not also roll back the standby cluster.
+    If you need to [roll back]({% link {{ page.version.version }}/upgrade-cockroach-version.md %}#roll-back-a-major-version-upgrade) an upgrade, you must do so before the upgrade has been finalized. Rolling back the upgrade on the primary cluster does not roll back the standby cluster.
     {{site.data.alerts.end}}
 
 1. [Finalize]({% link {{ page.version.version }}/upgrade-cockroach-version.md %}#finalize-a-major-version-upgrade-manually) the upgrade on the primary cluster's AppVC. 
@@ -41,35 +39,37 @@ To upgrade your primary and standby clusters:
 
 ## Upgrade ReaderVC
 
-If you have a [_reader virtual cluster (ReaderVC)_]({% link {{ page.version.version }}/read-from-standby.md %}), use the following steps to upgrade it by dropping and re-creating it:
+If you have a [_reader virtual cluster (ReaderVC)_]({% link {{ page.version.version }}/read-from-standby.md %}), you must upgrade it independently from the primary and standby clusters, after completing the main upgrade process. Use the following steps to upgrade your ReaderVC by dropping and re-creating it:
 
 1. After upgrading the AppVC on your primary cluster, wait for the replicated time to pass the time at which the upgrade completed.
 1. On the standby cluster, stop the ReaderVC service:
 
     {% include_cached copy-clipboard.html %}
     ~~~ sql
-    ALTER VIRTUAL CLUSTER <readervc-name> STOP SERVICE
+    ALTER VIRTUAL CLUSTER <readervc-name> STOP SERVICE;
     ~~~
 
 1. Drop the ReaderVC:
 
     {% include_cached copy-clipboard.html %}
     ~~~ sql
-    DROP VIRTUAL CLUSTER <readervc-name>
+    DROP VIRTUAL CLUSTER <readervc-name>;
     ~~~
 
-1. Back on the standby cluster, if the version is as expected, re-create the ReaderVC:
+1. On the standby cluster, re-create the ReaderVC:
 
     {% include_cached copy-clipboard.html %}
     ~~~ sql
-    ALTER VIRTUAL CLUSTER dest-system SET REPLICATION READ VIRTUAL CLUSTER
+    ALTER VIRTUAL CLUSTER dest-system SET REPLICATION READ VIRTUAL CLUSTER;
     ~~~
 
+At this point, the ReaderVC is on the same version as the standby cluster.
+
 ## Failover and fast failback during upgrade
 
-If you need to perform a [failover]({% link {{ page.version.version }}/failover-replication.md %}) while upgrading your clusters, you can do that using the normal process.
+If you need to, you can still perform a [failover]({% link {{ page.version.version }}/failover-replication.md %}) while upgrading your clusters.
 
-However, after performing a failover you cannot perform a [fast failback]({% link {{ page.version.version }}/failover-replication.md %}#failback) to the original primary cluster during the upgrade process. This is because at times during the upgrade the standby cluster is ahead of the primary cluster.
+However, after performing a failover you cannot perform a [fast failback]({% link {{ page.version.version }}/failover-replication.md %}#failback) to the original primary cluster while the standby cluster version is newer than the primary cluster version. This is because you cannot replicate data from a cluster on a newer version to a cluster on an older version. 
 
 ## Minor version upgrades