diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Revision history for futhark-server
 
+## 1.4.0.0 -- 2026-04-29
+
+* Replaced `cmdOutputs` with `cmdOutput`.
+
+* `cmdCall` now accepts only a single variable for the output.
+
 ## 1.3.3.0 -- 2026-03-30
 
 * Better `Show` instance for `ServerException`.
diff --git a/futhark-server.cabal b/futhark-server.cabal
--- a/futhark-server.cabal
+++ b/futhark-server.cabal
@@ -1,6 +1,6 @@
 cabal-version:      2.4
 name:               futhark-server
-version:            1.3.3.0
+version:            1.4.0.0
 synopsis: Client implementation of the Futhark server protocol.
 
 description: Provides an easy way to interact with a running Futhark
diff --git a/src/Futhark/Server.hs b/src/Futhark/Server.hs
--- a/src/Futhark/Server.hs
+++ b/src/Futhark/Server.hs
@@ -50,7 +50,7 @@
     cmdFree,
     cmdRename,
     cmdInputs,
-    cmdOutputs,
+    cmdOutput,
     cmdClear,
 
     -- ** Interrogation
@@ -419,9 +419,9 @@
 cmdStore s fname vars = helpCmd s "store" $ T.pack fname : vars
 
 -- | @call entrypoint outs... ins...@.
-cmdCall :: Server -> EntryName -> [VarName] -> [VarName] -> IO (Either CmdFailure [Text])
-cmdCall s entry outs ins =
-  sendCommand s "call" $ entry : outs ++ ins
+cmdCall :: Server -> EntryName -> VarName -> [VarName] -> IO (Either CmdFailure [Text])
+cmdCall s entry out ins =
+  sendCommand s "call" $ entry : out : ins
 
 -- | @free vars...@.
 cmdFree :: Server -> [VarName] -> IO (Maybe CmdFailure)
@@ -436,10 +436,10 @@
 cmdInputs s entry =
   fmap (map (inOutType InputType)) <$> sendCommand s "inputs" [entry]
 
--- | @outputs entryname@, with uniqueness represented as True.
-cmdOutputs :: Server -> EntryName -> IO (Either CmdFailure [OutputType])
-cmdOutputs s entry =
-  fmap (map (inOutType OutputType)) <$> sendCommand s "outputs" [entry]
+-- | @output entryname@, with uniqueness represented as True.
+cmdOutput :: Server -> EntryName -> IO (Either CmdFailure OutputType)
+cmdOutput s entry =
+  fmap (inOutType OutputType) <$> sendCommandSL s "output" [entry]
 
 -- | @clear@
 cmdClear :: Server -> IO (Maybe CmdFailure)