diff --git a/legion-discovery.cabal b/legion-discovery.cabal
--- a/legion-discovery.cabal
+++ b/legion-discovery.cabal
@@ -1,5 +1,5 @@
 name:                legion-discovery
-version:             0.2.1.0
+version:             0.2.1.1
 synopsis:            Initial project template from stack
 description:         Please see README.md
 homepage:            https://github.com/owensmurray/legion-discovery#readme
@@ -38,7 +38,7 @@
     data-default-class >= 0.0.1    && < 0.2,
     http-types         >= 0.9.1    && < 0.10,
     legion             >= 0.5      && < 0.6,
-    legion-extra       >= 0.1      && < 0.2,
+    legion-extra       >= 0.1.0.3  && < 0.2,
     monad-logger       >= 0.3.19   && < 0.4,
     scotty             >= 0.11.0   && < 0.12,
     scotty-resource    >= 0.1.1.0  && < 0.3,
diff --git a/src/Network/Legion/Discovery.hs b/src/Network/Legion/Discovery.hs
--- a/src/Network/Legion/Discovery.hs
+++ b/src/Network/Legion/Discovery.hs
@@ -223,6 +223,7 @@
 
 
 {- | The content type for ping requests. -}
+pattern PingRequestCT :: (IsString a, Eq a) => a
 pattern PingRequestCT = "application/vnd.legion-discovery.ping-request+json"