diff --git a/opennms-web-api/src/main/java/org/opennms/web/servlet/SpaRoutingFilter.java b/opennms-web-api/src/main/java/org/opennms/web/servlet/SpaRoutingFilter.java
index 7a37490a2457..e602c40b82cd 100644
--- a/opennms-web-api/src/main/java/org/opennms/web/servlet/SpaRoutingFilter.java
+++ b/opennms-web-api/src/main/java/org/opennms/web/servlet/SpaRoutingFilter.java
@@ -22,6 +22,7 @@
 package org.opennms.web.servlet;
 
 import java.io.IOException;
+import java.util.regex.Pattern;
 
 import javax.servlet.Filter;
 import javax.servlet.FilterChain;
@@ -31,31 +32,41 @@
 import javax.servlet.ServletResponse;
 import javax.servlet.annotation.WebFilter;
 import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletRequestWrapper;
 
 @WebFilter(asyncSupported = true, urlPatterns = "/*")
 public class SpaRoutingFilter implements Filter {
 
+    public static final String UI_VERSION_PROPERTY = "org.opennms.web.ui.version";
+    public static final String DEFAULT_VERSION = "default";
+
+    private static final Pattern SAFE_VERSION = Pattern.compile("[A-Za-z0-9._-]+");
+
     @Override
     public void doFilter(final ServletRequest request, final ServletResponse response, final FilterChain chain) throws IOException, ServletException {
         final HttpServletRequest httpServletRequest = (HttpServletRequest) request;
         final String uri = httpServletRequest.getRequestURI().substring(httpServletRequest.getContextPath().length());
-        if (isClientPath(uri)) {
-            chain.doFilter(new HttpServletRequestWrapper(httpServletRequest) {
-                @Override
-                public String getServletPath() {
-                    return "/ui/index.html";
-                }
-            }, response);
+
+        if (!uri.equals("/ui") && !uri.startsWith("/ui/")) {
+            chain.doFilter(request, response);
             return;
         }
-        chain.doFilter(request, response);
+
+        final String version = activeVersion();
+        final String suffix = isAsset(uri) ? uri.substring("/ui".length()) : "/index.html";
+        final String target = "/ui-versions/" + version + suffix;
+        request.getRequestDispatcher(target).forward(request, response);
+    }
+
+    private String activeVersion() {
+        final String value = System.getProperty(UI_VERSION_PROPERTY, DEFAULT_VERSION);
+        if (value.contains("..") || !SAFE_VERSION.matcher(value).matches()) {
+            return DEFAULT_VERSION;
+        }
+        return value;
     }
 
-    private boolean isClientPath(final String uri) {
-        return uri.startsWith("/ui/")
-                && !uri.startsWith("/ui/assets/")
-                && !uri.endsWith(".svg");
+    private boolean isAsset(final String uri) {
+        return uri.startsWith("/ui/assets/") || uri.endsWith(".svg");
     }
 
     @Override
diff --git a/opennms-web-api/src/test/java/org/opennms/web/servlet/SpaRoutingFilterTest.java b/opennms-web-api/src/test/java/org/opennms/web/servlet/SpaRoutingFilterTest.java
new file mode 100644
index 000000000000..efacc07ea113
--- /dev/null
+++ b/opennms-web-api/src/test/java/org/opennms/web/servlet/SpaRoutingFilterTest.java
@@ -0,0 +1,109 @@
+/*
+ * Licensed to The OpenNMS Group, Inc (TOG) under one or more
+ * contributor license agreements.  See the LICENSE.md file
+ * distributed with this work for additional information
+ * regarding copyright ownership.
+ *
+ * TOG licenses this file to You under the GNU Affero General
+ * Public License Version 3 (the "License") or (at your option)
+ * any later version.  You may not use this file except in
+ * compliance with the License.  You may obtain a copy of the
+ * License at:
+ *
+ *      https://www.gnu.org/licenses/agpl-3.0.txt
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+ * either express or implied.  See the License for the specific
+ * language governing permissions and limitations under the
+ * License.
+ */
+package org.opennms.web.servlet;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+
+import org.junit.After;
+import org.junit.Test;
+import org.springframework.mock.web.MockFilterChain;
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.mock.web.MockHttpServletResponse;
+
+public class SpaRoutingFilterTest {
+
+    private static final String PROP = "org.opennms.web.ui.version";
+
+    @After
+    public void clearProperty() {
+        System.clearProperty(PROP);
+    }
+
+    private MockHttpServletResponse runFilter(String uri, MockFilterChain chain) throws Exception {
+        MockHttpServletRequest req = new MockHttpServletRequest("GET", uri);
+        MockHttpServletResponse res = new MockHttpServletResponse();
+        new SpaRoutingFilter().doFilter(req, res, chain);
+        return res;
+    }
+
+    @Test
+    public void defaultVersion_spaDeepLink_forwardsToDefaultIndex() throws Exception {
+        MockFilterChain chain = new MockFilterChain();
+        MockHttpServletResponse res = runFilter("/ui/dashboard", chain);
+        assertEquals("/ui-versions/default/index.html", res.getForwardedUrl());
+        assertNull("filter chain should not be invoked when forwarding", chain.getRequest());
+    }
+
+    @Test
+    public void namedVersion_spaDeepLink_forwardsToActiveVersionIndex() throws Exception {
+        System.setProperty(PROP, "next");
+        MockHttpServletResponse res = runFilter("/ui/dashboard", new MockFilterChain());
+        assertEquals("/ui-versions/next/index.html", res.getForwardedUrl());
+    }
+
+    @Test
+    public void namedVersion_assetRequest_forwardsToActiveVersionAsset() throws Exception {
+        System.setProperty(PROP, "next");
+        MockHttpServletResponse res = runFilter("/ui/assets/index-abc123.js", new MockFilterChain());
+        assertEquals("/ui-versions/next/assets/index-abc123.js", res.getForwardedUrl());
+    }
+
+    @Test
+    public void namedVersion_svgAsset_forwardsToActiveVersionSvg() throws Exception {
+        System.setProperty(PROP, "next");
+        MockHttpServletResponse res = runFilter("/ui/logo.svg", new MockFilterChain());
+        assertEquals("/ui-versions/next/logo.svg", res.getForwardedUrl());
+    }
+
+    @Test
+    public void dottedVersionName_isAccepted() throws Exception {
+        System.setProperty(PROP, "35.1.0-beta");
+        MockHttpServletResponse res = runFilter("/ui/dashboard", new MockFilterChain());
+        assertEquals("/ui-versions/35.1.0-beta/index.html", res.getForwardedUrl());
+    }
+
+    @Test
+    public void slashInVersionName_fallsBackToDefault() throws Exception {
+        System.setProperty(PROP, "../etc/passwd");
+        MockHttpServletResponse res = runFilter("/ui/dashboard", new MockFilterChain());
+        assertEquals("/ui-versions/default/index.html", res.getForwardedUrl());
+    }
+
+    @Test
+    public void dotDotInVersionName_fallsBackToDefault() throws Exception {
+        System.setProperty(PROP, "..");
+        MockHttpServletResponse res = runFilter("/ui/dashboard", new MockFilterChain());
+        assertEquals("/ui-versions/default/index.html", res.getForwardedUrl());
+    }
+
+    @Test
+    public void nonUiRequest_passesThroughChainUnchanged() throws Exception {
+        MockHttpServletRequest req = new MockHttpServletRequest("GET", "/some/other/path");
+        MockHttpServletResponse res = new MockHttpServletResponse();
+        MockFilterChain chain = new MockFilterChain();
+        new SpaRoutingFilter().doFilter(req, res, chain);
+        assertNull("non-/ui request must not be forwarded", res.getForwardedUrl());
+        assertNotNull("non-/ui request must be passed through the chain", chain.getRequest());
+    }
+}
diff --git a/opennms-webapp/pom.xml b/opennms-webapp/pom.xml
index ad99d9fe848c..87704b55a955 100644
--- a/opennms-webapp/pom.xml
+++ b/opennms-webapp/pom.xml
@@ -50,10 +50,10 @@
                 <artifactItem>
                   <groupId>org.opennms</groupId>
                   <artifactId>org.opennms.ui</artifactId>
-                  <version>${project.version}</version>
+                  <version>${opennms.ui.version}</version>
                   <classifier>dist</classifier>
                   <overWrite>true</overWrite>
-                  <outputDirectory>target/opennms-webapp-${project.version}/ui</outputDirectory>
+                  <outputDirectory>target/opennms-webapp-${project.version}/ui-versions/default</outputDirectory>
                 </artifactItem>
               </artifactItems>
               <excludes>META-INF/**</excludes>
diff --git a/pom.xml b/pom.xml
index 4a8f7621e67d..c743b297893f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -2024,6 +2024,8 @@
     <frontendPluginVersion>1.14.2</frontendPluginVersion>
     <nodeVersion>v22.22.2</nodeVersion>
     <pnpmVersion>10.24.0</pnpmVersion>
+    <!-- UI version — override to ship a different UI without rebuilding the backend -->
+    <opennms.ui.version>${project.version}</opennms.ui.version>
 
     <!-- configuration manager -->
     <xmlschemaVersion>2.3.1</xmlschemaVersion>