diff --git a/CHANGELOG.md b/CHANGELOG.md
index e69de29bb2d..c86f3ecd431 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -0,0 +1 @@
+- Enable single project mode for the database emulator (#5068).
diff --git a/src/emulator/controller.ts b/src/emulator/controller.ts
index 022653ac751..8e2ba913a09 100644
--- a/src/emulator/controller.ts
+++ b/src/emulator/controller.ts
@@ -712,6 +712,8 @@ export async function startAll(
       port: databaseAddr.port,
       projectId,
       auto_download: true,
+      // Only set the flag (at all) if singleProjectMode is enabled.
+      single_project_mode: singleProjectModeEnabled ? "Warning" : undefined,
     };
 
     // Try to fetch the default RTDB instance for a project, but don't hard-fail if we
diff --git a/src/emulator/databaseEmulator.ts b/src/emulator/databaseEmulator.ts
index 786f4d1995f..6f83184de21 100644
--- a/src/emulator/databaseEmulator.ts
+++ b/src/emulator/databaseEmulator.ts
@@ -21,6 +21,7 @@ export interface DatabaseEmulatorArgs {
   functions_emulator_port?: number;
   functions_emulator_host?: string;
   auto_download?: boolean;
+  single_project_mode?: string;
 }
 
 export class DatabaseEmulator implements EmulatorInstance {
diff --git a/src/emulator/downloadableEmulators.ts b/src/emulator/downloadableEmulators.ts
index c342e2a2431..f8e385334e5 100644
--- a/src/emulator/downloadableEmulators.ts
+++ b/src/emulator/downloadableEmulators.ts
@@ -27,14 +27,14 @@ const CACHE_DIR =
 
 export const DownloadDetails: { [s in DownloadableEmulators]: EmulatorDownloadDetails } = {
   database: {
-    downloadPath: path.join(CACHE_DIR, "firebase-database-emulator-v4.9.0.jar"),
-    version: "4.9.0",
+    downloadPath: path.join(CACHE_DIR, "firebase-database-emulator-v4.10.0.jar"),
+    version: "4.10.0",
     opts: {
       cacheDir: CACHE_DIR,
       remoteUrl:
-        "https://storage.googleapis.com/firebase-preview-drop/emulator/firebase-database-emulator-v4.9.0.jar",
-      expectedSize: 34204485,
-      expectedChecksum: "1c3f5974f0ee5559ebf27b56f2e62108",
+        "https://storage.googleapis.com/firebase-preview-drop/emulator/firebase-database-emulator-v4.10.0.jar",
+      expectedSize: 34230230,
+      expectedChecksum: "e99b23f0e723813de4f4ea0e879b46b0",
       namePrefix: "firebase-database-emulator",
     },
   },
@@ -144,7 +144,13 @@ const Commands: { [s in DownloadableEmulators]: DownloadableEmulatorCommand } =
   database: {
     binary: "java",
     args: ["-Duser.language=en", "-jar", getExecPath(Emulators.DATABASE)],
-    optionalArgs: ["port", "host", "functions_emulator_port", "functions_emulator_host"],
+    optionalArgs: [
+      "port",
+      "host",
+      "functions_emulator_port",
+      "functions_emulator_host",
+      "single_project_mode",
+    ],
     joinArgs: false,
   },
   firestore: {