diff --git a/diagrams-postscript.cabal b/diagrams-postscript.cabal
--- a/diagrams-postscript.cabal
+++ b/diagrams-postscript.cabal
@@ -1,5 +1,5 @@
 Name:                diagrams-postscript
-Version:             1.5.1
+Version:             1.5.1.1
 Synopsis:            Postscript backend for diagrams drawing EDSL
 Description:         This package provides a modular backend for rendering
                      diagrams created with the diagrams EDSL using Postscript.
@@ -23,7 +23,7 @@
 Category:            Graphics
 Build-type:          Simple
 Cabal-version:       1.18
-Tested-with:         GHC ==8.4.4 || ==8.6.5 || ==8.8.4 || ==8.10.4 || ==9.0.1 || ==9.2.1
+Tested-with:         GHC ==8.4.4 || ==8.6.5 || ==8.8.4 || ==8.10.7 || ==9.0.2 || ==9.2.4 || ==9.4.1
 Source-repository head
   type:     git
   location: https://github.com/diagrams/diagrams-postscript.git
@@ -34,17 +34,17 @@
                        Diagrams.Backend.Postscript.CmdLine
                        Graphics.Rendering.Postscript
   Hs-source-dirs:      src
-  Build-depends:       base >= 4.8 && < 4.17,
+  Build-depends:       base >= 4.8 && < 4.18,
                        bytestring >= 0.9 && <0.12,
-                       mtl >= 2.0 && < 2.3,
+                       mtl >= 2.0 && < 2.4,
                        diagrams-core >= 1.3 && < 1.6,
-                       diagrams-lib >= 1.3 && < 1.5,
+                       diagrams-lib >= 1.4.5 && < 1.5,
                        data-default-class < 0.2,
                        statestack >= 0.2 && < 0.4,
                        split >= 0.1.2 && < 0.3,
                        monoid-extras >= 0.3 && < 0.7,
                        semigroups >= 0.3.4 && < 0.21,
-                       lens >= 4.0 && < 5.2,
+                       lens >= 4.0 && < 5.3,
                        containers >= 0.3 && < 0.7,
                        hashable >= 1.1 && < 1.5
 
diff --git a/src/Diagrams/Backend/Postscript.hs b/src/Diagrams/Backend/Postscript.hs
--- a/src/Diagrams/Backend/Postscript.hs
+++ b/src/Diagrams/Backend/Postscript.hs
@@ -8,6 +8,7 @@
 {-# LANGUAGE NoMonomorphismRestriction #-}
 {-# LANGUAGE TemplateHaskell           #-}
 {-# LANGUAGE TypeFamilies              #-}
+{-# LANGUAGE TypeOperators             #-}
 {-# LANGUAGE TypeSynonymInstances      #-}
 {-# LANGUAGE ViewPatterns              #-}
 -----------------------------------------------------------------------------
diff --git a/src/Graphics/Rendering/Postscript.hs b/src/Graphics/Rendering/Postscript.hs
--- a/src/Graphics/Rendering/Postscript.hs
+++ b/src/Graphics/Rendering/Postscript.hs
@@ -86,6 +86,7 @@
 import           Data.Monoid                (mconcat, mempty)
 #endif
 import           Control.Lens               (Lens', makeLenses, use, (%=), (.=))
+import           Control.Monad
 import           Control.Monad.State.Strict
 import qualified Data.ByteString.Builder    as B
 import           Data.Char                  (isPrint, ord)