a small correction ins the upgrade process. (#2350)

Co-authored-by: Karen Metts <[email protected]>

docs/en/install-upgrade/upgrading-stack.asciidoc

@@ -63,7 +63,7 @@ even if you opt to do a full-cluster restart of your {es} cluster.**
 Alternatively, you can create a new {version} deployment and reindex from remote.
 For more information, see <<upgrading-reindex, Reindex to upgrade>>.
 
-Beats and Logstash 7.n are compatible with {es} {version} 
+{beats} and {ls} {prev-major-last} are compatible with {es} {version} 
 to give you flexibility in scheduling the upgrade.
 
 .Remote cluster compatibility