diff --git a/agent/src/Lib/Types/Emver.hs b/agent/src/Lib/Types/Emver.hs
index 0cceeed9e..534d6642c 100644
--- a/agent/src/Lib/Types/Emver.hs
+++ b/agent/src/Lib/Types/Emver.hs
@@ -56,6 +56,8 @@ instance Show Version where
         let postfix = if q == 0 then "" else '.' : show q in show x <> "." <> show y <> "." <> show z <> postfix
 instance IsString Version where
     fromString s = either error id $ Atto.parseOnly parseVersion (T.pack s)
+instance Read Version where
+    readsPrec i = 
 
 -- | A change in the value found at 'major' implies a breaking change in the API that this version number describes
 major :: Version -> Word
diff --git a/agent/src/Lib/Types/Emver/Orphans.hs b/agent/src/Lib/Types/Emver/Orphans.hs
index 1af62533d..84c04956c 100644
--- a/agent/src/Lib/Types/Emver/Orphans.hs
+++ b/agent/src/Lib/Types/Emver/Orphans.hs
@@ -3,16 +3,17 @@ module Lib.Types.Emver.Orphans where
 
 import           Startlude
 
+import           Control.Monad.Fail
 import           Data.Aeson
-
-import           Lib.Types.Emver
+import qualified Data.Attoparsec.Text          as Atto
+import qualified Data.Text                     as T
 import           Database.Persist
 import           Database.Persist.Sql
-import qualified Data.Attoparsec.Text          as Atto
-import           Control.Monad.Fail
-import qualified Data.Text                     as T
+import           Web.HttpApiData
 import           Yesod.Core.Dispatch
 
+import           Lib.Types.Emver
+
 instance ToJSON Version where
     toJSON = String . show
 instance FromJSON Version where
@@ -38,3 +39,10 @@ instance PersistFieldSql Version where
 instance PathPiece VersionRange where
     toPathPiece   = show
     fromPathPiece = hush . Atto.parseOnly parseRange
+
+instance FromHttpApiData Version where
+    parseUrlPiece = first toS . Atto.parseOnly parseVersion
+
+instance PathPiece Version where
+    toPathPiece   = show
+    fromPathPiece = hush . Atto.parseOnly parseVersion
diff --git a/agent/src/Model.hs b/agent/src/Model.hs
index 308c813d1..336548d7d 100644
--- a/agent/src/Model.hs
+++ b/agent/src/Model.hs
@@ -59,4 +59,7 @@ BackupRecord sql=backup
 IconDigest
     Id AppId
     tag (Digest MD5)
+
+WelcomeAck
+    Id Version
 |]