Document master/manager rename in Upgrader9to10 re #1922 (#1927)
diff --git a/server/manager/src/main/java/org/apache/accumulo/manager/upgrade/Upgrader9to10.java b/server/manager/src/main/java/org/apache/accumulo/manager/upgrade/Upgrader9to10.java
index d88ebd2..41347a5 100644
--- a/server/manager/src/main/java/org/apache/accumulo/manager/upgrade/Upgrader9to10.java
+++ b/server/manager/src/main/java/org/apache/accumulo/manager/upgrade/Upgrader9to10.java
@@ -95,7 +95,17 @@
import com.google.common.base.Preconditions;
/**
- * Handles upgrading from 2.0 to 2.1
+ * Handles upgrading from 2.0 to 2.1.
+ * <ul>
+ * <li><strong>Rename master properties (Issue
+ * <a href="https://github.com/apache/accumulo/issues/1640">#1640</a>):</strong> Rename any
+ * ZooKeeper system properties that start with "master." to the equivalent property starting with
+ * "manager." instead (see the {@code renameOldMasterPropsinZK(ServerContext)} method). Note that
+ * this change was part of a larger effort to replace references to master with manager. See issues
+ * <a href="https://github.com/apache/accumulo/issues/1641">#1641</a>,
+ * <a href="https://github.com/apache/accumulo/issues/1642">#1642</a>, and
+ * <a href="https://github.com/apache/accumulo/issues/1643">#1643</a> as well.</li>
+ * </ul>
*/
public class Upgrader9to10 implements Upgrader {
