diff --git a/toolkit/components/telemetry/TelemetryPing.jsm b/toolkit/components/telemetry/TelemetryPing.jsm
index 2389d77e6cfb..b2bf12467be0 100644
--- a/toolkit/components/telemetry/TelemetryPing.jsm
+++ b/toolkit/components/telemetry/TelemetryPing.jsm
@@ -554,7 +554,9 @@ let Impl = {
   doPing: function doPing(ping, isPersisted) {
     this._log.trace("doPing - Server " + this._server + ", Persisted " + isPersisted);
     let deferred = Promise.defer();
-    let url = this._server + this.submissionPath(ping);
+    let isNewPing = isNewPingFormat(ping);
+    let version = isNewPing ? PING_FORMAT_VERSION : 1;
+    let url = this._server + this.submissionPath(ping) + "?v=" + version;
     let request = Cc["@mozilla.org/xmlextras/xmlhttprequest;1"]
                   .createInstance(Ci.nsIXMLHttpRequest);
     request.mozBackgroundRequest = true;
@@ -587,7 +589,7 @@ let Impl = {
     request.addEventListener("load", handler(true).bind(this), false);
 
     // If that's a legacy ping format, just send its payload.
-    let networkPayload = isNewPingFormat(ping) ? ping : ping.payload;
+    let networkPayload = isNewPing ? ping : ping.payload;
     request.setRequestHeader("Content-Encoding", "gzip");
     let converter = Cc["@mozilla.org/intl/scriptableunicodeconverter"]
                     .createInstance(Ci.nsIScriptableUnicodeConverter);
diff --git a/toolkit/components/telemetry/tests/unit/test_TelemetryPing.js b/toolkit/components/telemetry/tests/unit/test_TelemetryPing.js
index 1b5fac2f06bb..27648c3769f3 100644
--- a/toolkit/components/telemetry/tests/unit/test_TelemetryPing.js
+++ b/toolkit/components/telemetry/tests/unit/test_TelemetryPing.js
@@ -220,6 +220,14 @@ add_task(function* test_simplePing() {
 
   yield sendPing(false, false);
   let request = yield gRequestIterator.next();
+
+  // Check that we have a version query parameter in the URL.
+  Assert.notEqual(request.queryString, "");
+
+  // Make sure the version in the query string matches the new ping format version.
+  let params = request.queryString.split("&");
+  Assert.ok(params.find(p => p == ("v=" + PING_FORMAT_VERSION)));
+
   let ping = decodeRequestPayload(request);
   checkPingFormat(ping, TEST_PING_TYPE, false, false);
 });
diff --git a/toolkit/components/telemetry/tests/unit/test_TelemetrySendOldPings.js b/toolkit/components/telemetry/tests/unit/test_TelemetrySendOldPings.js
index 854483b6945a..fb5452766fd0 100644
--- a/toolkit/components/telemetry/tests/unit/test_TelemetrySendOldPings.js
+++ b/toolkit/components/telemetry/tests/unit/test_TelemetrySendOldPings.js
@@ -356,6 +356,55 @@ add_task(function* test_overdue_pings_trigger_send() {
   yield resetTelemetry();
 });
 
+/**
+ * Create a ping in the old format, send it, and make sure the request URL contains
+ * the correct version query parameter.
+ */
+add_task(function* test_overdue_old_format() {
+  // A test ping in the old, standard format.
+  const PING_OLD_FORMAT = {
+    slug: "1234567abcd",
+    reason: "test-ping",
+    payload: {
+      info: {
+        reason: "test-ping",
+        OS: "XPCShell",
+        appID: "SomeId",
+        appVersion: "1.0",
+        appName: "XPCShell",
+        appBuildID: "123456789",
+        appUpdateChannel: "Test",
+        platformBuildID: "987654321",
+      },
+    },
+  };
+
+  const filePath =
+    Path.join(Constants.Path.profileDir, PING_SAVE_FOLDER, PING_OLD_FORMAT.slug);
+
+  // Write the ping to file and make it overdue.
+  yield TelemetryFile.savePing(PING_OLD_FORMAT, true);
+  yield File.setDates(filePath, null, Date.now() - OVERDUE_PING_FILE_AGE);
+
+  let receivedPings = 0;
+  // Register a new prefix handler to validate the URL.
+  gHttpServer.registerPrefixHandler("/submit/telemetry/", request => {
+    // Check that we have a version query parameter in the URL.
+    Assert.notEqual(request.queryString, "");
+
+    // Make sure the version in the query string matches the old ping format version.
+    let params = request.queryString.split("&");
+    Assert.ok(params.find(p => p == "v=1"));
+
+    receivedPings++;
+  });
+
+  yield startTelemetry();
+  Assert.equal(receivedPings, 1, "We must receive a ping in the old format.");
+
+  yield resetTelemetry();
+});
+
 add_task(function* teardown() {
   yield stopHttpServer();
 });