diff --git a/lib/src/main/java/io/ably/lib/transport/Defaults.java b/lib/src/main/java/io/ably/lib/transport/Defaults.java
index 09f05edea..d7627939d 100644
--- a/lib/src/main/java/io/ably/lib/transport/Defaults.java
+++ b/lib/src/main/java/io/ably/lib/transport/Defaults.java
@@ -8,9 +8,14 @@
 import java.util.Locale;
 
 public class Defaults {
-    /* versions */
-    public static final float ABLY_VERSION_NUMBER   = 1.1f;
+    public static final float ABLY_VERSION_NUMBER   = 1.0f;
+
+    /**
+     * The level of compatibility with the Ably service that this SDK supports, also referred to as the 'wire protocol version'.
+     * This value is presented as a string, as specified in G4a.
+     */
     public static final String ABLY_VERSION         = new DecimalFormat("0.0", new DecimalFormatSymbols(Locale.ENGLISH)).format(ABLY_VERSION_NUMBER);
+
     public static final String ABLY_AGENT_VERSION   = String.format("%s/%s", "ably-java", BuildConfig.VERSION);
 
     /* params */
diff --git a/lib/src/test/java/io/ably/lib/test/realtime/RealtimeHttpHeaderTest.java b/lib/src/test/java/io/ably/lib/test/realtime/RealtimeHttpHeaderTest.java
index 404a06511..704ec0ec8 100644
--- a/lib/src/test/java/io/ably/lib/test/realtime/RealtimeHttpHeaderTest.java
+++ b/lib/src/test/java/io/ably/lib/test/realtime/RealtimeHttpHeaderTest.java
@@ -81,7 +81,7 @@ public void realtime_websocket_param_test() {
              * Defaults.ABLY_VERSION_PARAM, as ultimately the request param has been derived from those values.
              */
             assertEquals("Verify correct version", requestParameters.get("v"),
-                    Collections.singletonList("1.1"));
+                    Collections.singletonList("1.0"));
 
             /* Spec RSC7d3
              * This test should not directly validate version against Defaults.ABLY_AGENT_VERSION, nor
diff --git a/lib/src/test/java/io/ably/lib/test/rest/HttpHeaderTest.java b/lib/src/test/java/io/ably/lib/test/rest/HttpHeaderTest.java
index a46e320f4..d83d04a13 100644
--- a/lib/src/test/java/io/ably/lib/test/rest/HttpHeaderTest.java
+++ b/lib/src/test/java/io/ably/lib/test/rest/HttpHeaderTest.java
@@ -84,7 +84,7 @@ public void header_lib_channel_publish() {
              * from those values.
              */
             Assert.assertNotNull("Expected headers", headers);
-            Assert.assertEquals(headers.get("x-ably-version"), "1.1");
+            Assert.assertEquals(headers.get("x-ably-version"), "1.0");
             Assert.assertEquals(headers.get("ably-agent"), expectedAblyAgentHeader);
         } catch (AblyException e) {
             e.printStackTrace();
diff --git a/lib/src/test/java/io/ably/lib/transport/DefaultsTest.java b/lib/src/test/java/io/ably/lib/transport/DefaultsTest.java
index 24b981696..021387da4 100644
--- a/lib/src/test/java/io/ably/lib/transport/DefaultsTest.java
+++ b/lib/src/test/java/io/ably/lib/transport/DefaultsTest.java
@@ -9,7 +9,7 @@ public class DefaultsTest {
 
     @Test
     public void versions() {
-        assertThat(Defaults.ABLY_VERSION, is("1.1"));
+        assertThat(Defaults.ABLY_VERSION, is("1.0"));
     }
 
     @Test