diff --git a/unstable/wlr-layer-shell-unstable-v1.xml b/unstable/wlr-layer-shell-unstable-v1.xml
index e9f27e4..c217dcc 100644
--- a/unstable/wlr-layer-shell-unstable-v1.xml
+++ b/unstable/wlr-layer-shell-unstable-v1.xml
@@ -25,7 +25,7 @@
     THIS SOFTWARE.
   </copyright>
 
-  <interface name="zwlr_layer_shell_v1" version="5">
+  <interface name="zwlr_layer_shell_v1" version="6">
     <description summary="create surfaces that are layers of the desktop">
       Clients can use this interface to assign the surface_layer role to
       wl_surfaces. Such surfaces are assigned to a "layer" of the output and
@@ -368,6 +368,7 @@
       <entry name="invalid_anchor" value="2" summary="anchor bitfield is invalid"/>
       <entry name="invalid_keyboard_interactivity" value="3" summary="keyboard interactivity is invalid"/>
       <entry name="invalid_exclusive_edge" value="4" summary="exclusive edge is invalid given the surface anchors"/>
+      <entry name="invalid_layer" value="5" since="6" summary="layer value is invalid"/>
     </enum>
 
     <enum name="anchor" bitfield="true">