diff --git a/PrettyDevList.hs b/PrettyDevList.hs
--- a/PrettyDevList.hs
+++ b/PrettyDevList.hs
@@ -33,7 +33,7 @@
 import Data.List                 ( intersperse, length, map, maximum
                                  , partition, transpose, zipWith
                                  )
-import Data.Maybe                ( maybe )
+import Data.Maybe                ( Maybe(Nothing, Just), maybe )
 import Data.Word                 ( Word8, Word16 )
 import Prelude                   ( (+), fromIntegral, fromInteger, fromRational )
 import System.IO                 ( IO )
@@ -58,7 +58,7 @@
                                  , deviceProtocol, deviceReleaseNumber
                                  , deviceSerialNumberStrIx, deviceSubClass
                                  , deviceUSBSpecReleaseNumber, deviceVendorId
-                                 , BCD4
+                                 , ReleaseNumber
                                  , ConfigDesc
                                  , configAttribs, configInterfaces
                                  , configMaxPower, configNumInterfaces
@@ -210,12 +210,12 @@
 unknown ∷ Doc
 unknown = text "unknown"
 
-ppBCD4 ∷ BCD4 → Doc
-ppBCD4 (a, b, c, d) = hcat ∘ punctuate (char '.') $ map pretty [a, b, c, d]
+ppReleaseNumber ∷ ReleaseNumber → Doc
+ppReleaseNumber (a, b, c, d) = hcat ∘ punctuate (char '.') $ map pretty [a, b, c, d]
 
-ppStringDesc ∷ PPStyle → Device → StrIx → IO Doc
-ppStringDesc _     _   0  = return empty
-ppStringDesc style dev ix = catchUSBException
+ppStringDesc ∷ PPStyle → Device → Maybe StrIx → IO Doc
+ppStringDesc _     _   Nothing = return empty
+ppStringDesc style dev (Just ix) = catchUSBException
     ( withDevice dev $ \devH →
         fmap (descrStyle style)
               $ getStrDescFirstLang devH
@@ -366,7 +366,7 @@
         protocolDoc = ppDevProtocol style db classId subClassId protocolId
 
     return $ columns 2
-      [ field' "USB specification" [ versionStyle' ∘ ppBCD4
+      [ field' "USB specification" [ versionStyle' ∘ ppReleaseNumber
                                    $ deviceUSBSpecReleaseNumber desc
                                    ]
       , field' "Class"             [usbNumStyle' classId, classDoc]
@@ -379,7 +379,7 @@
       , field' "Product ID"        [ usbNumStyle' $ text "0x" <> ppId productId
                                    , ppProductName style db vendorId productId id
                                    ]
-      , field' "Release number"    [ versionStyle' ∘ ppBCD4
+      , field' "Release number"    [ versionStyle' ∘ ppReleaseNumber
                                    $ deviceReleaseNumber desc
                                    ]
       , field' "Manufacturer"      [descrAddrStyle' manufacturerIx, manufacturerDoc]
diff --git a/ls-usb.cabal b/ls-usb.cabal
--- a/ls-usb.cabal
+++ b/ls-usb.cabal
@@ -1,5 +1,5 @@
 name:          ls-usb
-version:       0.1.0.6
+version:       0.1.0.7
 cabal-version: >= 1.6
 build-type:    Simple
 stability:     beta
@@ -19,12 +19,12 @@
 
 executable ls-usb
   build-depends: ansi-wl-pprint       >= 0.5.1   && < 0.6
-               , base                 >= 4.0     && < 4.3
+               , base                 >= 4.0     && < 4.4
                , base-unicode-symbols >= 0.1.1   && < 0.3
                , bytestring           >= 0.9.1   && < 0.10
                , cmdargs              == 0.3.*
-               , usb                  == 0.5.*
-               , usb-safe             == 0.8.*
+               , usb                  == 0.6.*
+               , usb-safe             == 0.11.*
                , usb-id-database      >= 0.4.0.2 && < 0.5
   ghc-options: -Wall -fno-warn-orphans
   main-is: ls-usb.hs