diff --git a/changelog.html b/changelog.html
index 2a0aa6a72..5192092ce 100644
--- a/changelog.html
+++ b/changelog.html
@@ -48,6 +48,7 @@ <h1>
 <ul>
     <li>[<a href="https://github.com/igniterealtime/openfire-restAPI-plugin/issues/213">#213</a>] - Improve setting a subject in a chat room</li>
     <li>[<a href="https://github.com/igniterealtime/openfire-restAPI-plugin/issues/217">#217</a>] - Add Hurl e2e tests, and CI to run them</li>
+    <li>Ensure cross-database compatibility for unread message count query</li>
 </ul>
 
 <p><b>1.12.0</b> July 4, 2025</p>
diff --git a/plugin.xml b/plugin.xml
index cf76295bb..d4c3d310a 100644
--- a/plugin.xml
+++ b/plugin.xml
@@ -6,7 +6,7 @@
     <description>Allows administration over a RESTful API.</description>
     <author>Roman Soldatow</author>
     <version>${project.version}</version>
-    <date>2025-10-02</date>
+    <date>2025-10-09</date>
     <minServerVersion>5.0.0</minServerVersion>
     <adminconsole>
         <tab id="tab-server">
diff --git a/src/java/org/jivesoftware/openfire/plugin/rest/controller/MsgArchiveController.java b/src/java/org/jivesoftware/openfire/plugin/rest/controller/MsgArchiveController.java
index f87ad819c..004a3abc0 100644
--- a/src/java/org/jivesoftware/openfire/plugin/rest/controller/MsgArchiveController.java
+++ b/src/java/org/jivesoftware/openfire/plugin/rest/controller/MsgArchiveController.java
@@ -22,6 +22,7 @@
 import java.sql.SQLException;
 
 import org.jivesoftware.database.DbConnectionManager;
+import org.jivesoftware.database.DbConnectionManager.DatabaseType;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.xmpp.packet.JID;
@@ -36,12 +37,29 @@ public class MsgArchiveController {
 
     /** The Constant INSTANCE. */
     public static final MsgArchiveController INSTANCE = new MsgArchiveController();
+    /**
+     * Builds the SQL query for counting unread messages based on the underlying database type.
+     *
+     * @param databaseType the database connection used to detect the database product name
+     * @return the database-specific SQL query string for counting unread messages
+     */
+    private String buildUserMessageCountQuery(DatabaseType databaseType) {
+        String castExpr;
+        switch (databaseType) {
+            case mysql:
+                castExpr = "CAST(p.offlineDate AS SIGNED)"; break;
+            case oracle:
+                castExpr = "CAST(p.offlineDate AS NUMBER)"; break;
+            default:
+                // PostgreSQL, SQL Server, Sybase — all understand BIGINT in CAST
+                castExpr = "CAST(p.offlineDate AS BIGINT)";
+                break;
+        }
 
-    /** The Constant USER_MESSAGE_COUNT. */
-    private static final String USER_MESSAGE_COUNT = "select COUNT(1) from ofMessageArchive a " +
-            "join ofPresence p on (a.sentDate > p.offlineDate) " +
+        return "SELECT COUNT(1) FROM ofMessageArchive a " +
+            "JOIN ofPresence p ON (a.sentDate > " + castExpr + ") " +
             "WHERE a.toJID = ? AND p.username = ?";
-
+    }
     /**
      * Gets the single instance of MsgArchiveController.
      *
@@ -70,7 +88,9 @@ public int getUnReadMessagesCount(JID jid) {
         ResultSet rs = null;
         try {
             con = DbConnectionManager.getConnection();
-            pstmt = con.prepareStatement(USER_MESSAGE_COUNT);
+            DatabaseType databaseType = DbConnectionManager.getDatabaseType();
+            String userMessageCountQuery = buildUserMessageCountQuery(databaseType);
+            pstmt = con.prepareStatement(userMessageCountQuery);
             pstmt.setString(1, jid.toBareJID());
             pstmt.setString(2, jid.getNode());
             rs = pstmt.executeQuery();