diff --git a/copilot-c99/CHANGELOG b/copilot-c99/CHANGELOG
index 846861da..12382d90 100644
--- a/copilot-c99/CHANGELOG
+++ b/copilot-c99/CHANGELOG
@@ -1,3 +1,6 @@
+2023-11-05
+        * Replace uses of deprecated functions. (#457)
+
 2023-09-07
         * Version bump (3.16.1). (#455)
         * Clean code. (#453)
diff --git a/copilot-c99/src/Copilot/Compile/C99/CodeGen.hs b/copilot-c99/src/Copilot/Compile/C99/CodeGen.hs
index b9c3feb8..23b9de25 100644
--- a/copilot-c99/src/Copilot/Compile/C99/CodeGen.hs
+++ b/copilot-c99/src/Copilot/Compile/C99/CodeGen.hs
@@ -33,7 +33,7 @@ import qualified Language.C99.Simple as C
 
 -- Internal imports: Copilot
 import Copilot.Core ( Expr (..), Id, Stream (..), Struct (..), Trigger (..),
-                      Type (..), UExpr (..), Value (..), fieldname, tysize )
+                      Type (..), UExpr (..), Value (..), fieldName, typeSize )
 
 -- Internal imports
 import Copilot.Compile.C99.Error    ( impossible )
@@ -67,17 +67,17 @@ mkExtCpyDecln (External _name cpyName ty) = decln
 mkStructDecln :: Struct a => Type a -> C.Decln
 mkStructDecln (Struct x) = C.TypeDecln struct
   where
-    struct = C.TypeSpec $ C.StructDecln (Just $ typename x) fields
+    struct = C.TypeSpec $ C.StructDecln (Just $ typeName x) fields
     fields = NonEmpty.fromList $ map mkField (toValues x)
 
     mkField :: Value a -> C.FieldDecln
-    mkField (Value ty field) = C.FieldDecln (transType ty) (fieldname field)
+    mkField (Value ty field) = C.FieldDecln (transType ty) (fieldName field)
 
 -- | Write a forward struct declaration.
 mkStructForwDecln :: Struct a => Type a -> C.Decln
 mkStructForwDecln (Struct x) = C.TypeDecln struct
   where
-    struct = C.TypeSpec $ C.Struct (typename x)
+    struct = C.TypeSpec $ C.Struct (typeName x)
 
 -- * Ring buffers
 
@@ -134,7 +134,7 @@ mkGenFunArray name nameArg expr ty@(Array _) =
 
     -- Copy expression to output argument
     stmts = [ C.Expr $ memcpy (C.Ident nameArg) cExpr size ]
-    size  = C.LitInt (fromIntegral $ tysize ty)
+    size  = C.LitInt (fromIntegral $ typeSize ty)
               C..* C.SizeOfType (C.TypeName $ tyElemName ty)
 
 mkGenFunArray _name _nameArg _expr _ty =
@@ -180,7 +180,7 @@ mkStep cSettings streams triggers exts =
               where
                 dest = C.Index buffVar indexVar
                 size = C.LitInt
-                           (fromIntegral $ tysize ty)
+                           (fromIntegral $ typeSize ty)
                            C..* C.SizeOfType (C.TypeName (tyElemName ty))
             _       -> C.Expr $
                            C.Index buffVar indexVar C..= C.Ident tmpVar
@@ -203,7 +203,7 @@ mkStep cSettings streams triggers exts =
         where
           exVar  = C.Ident cpyName
           locVar = C.Ident name
-          size   = C.LitInt (fromIntegral $ tysize ty)
+          size   = C.LitInt (fromIntegral $ typeSize ty)
                      C..* C.SizeOfType (C.TypeName (tyElemName ty))
 
       _       -> C.Ident cpyName C..= C.Ident name
diff --git a/copilot-c99/src/Copilot/Compile/C99/Expr.hs b/copilot-c99/src/Copilot/Compile/C99/Expr.hs
index faa522b8..1c810899 100644
--- a/copilot-c99/src/Copilot/Compile/C99/Expr.hs
+++ b/copilot-c99/src/Copilot/Compile/C99/Expr.hs
@@ -14,7 +14,7 @@ import qualified Language.C99.Simple as C
 
 -- Internal imports: Copilot
 import Copilot.Core ( Expr (..), Field (..), Op1 (..), Op2 (..), Op3 (..),
-                      Type (..), Value (..), accessorname, arrayelems,
+                      Type (..), Value (..), accessorName, arrayElems,
                       toValues )
 
 -- Internal imports
@@ -96,7 +96,7 @@ transOp1 op e =
     Floor    ty   -> funCall (specializeMathFunName ty "floor") [e]
     BwNot    _    -> (C..~) e
     Cast     _ ty -> C.Cast (transTypeName ty) e
-    GetField (Struct _)  _ f -> C.Dot e (accessorname f)
+    GetField (Struct _)  _ f -> C.Dot e (accessorName f)
 
 -- | Translates a Copilot binary operator and its arguments into a C99
 -- expression.
@@ -239,7 +239,7 @@ constTy ty = case ty of
   Float     -> explicitTy ty . C.LitFloat
   Double    -> explicitTy ty . C.LitDouble
   Struct _  -> C.InitVal (transTypeName ty) . constStruct . toValues
-  Array ty' -> C.InitVal (transTypeName ty) . constArray ty' . arrayelems
+  Array ty' -> C.InitVal (transTypeName ty) . constArray ty' . arrayElems
 
 -- | Transform a Copilot Core literal, based on its value and type, into a C99
 -- initializer.
@@ -265,7 +265,7 @@ constInit ty val = case ty of
   -- whole expression as an array of two int32_t's (as opposed to a nested
   -- array). This can either lead to compile-time errors (if you're lucky) or
   -- incorrect runtime semantics (if you're unlucky).
-  Array ty' -> C.InitList $ constArray ty' $ arrayelems val
+  Array ty' -> C.InitList $ constArray ty' $ arrayElems val
 
   -- We use InitArray to initialize a struct because the syntax used for
   -- initializing arrays and structs is compatible. For instance, {1, 2} works
diff --git a/copilot-c99/src/Copilot/Compile/C99/Type.hs b/copilot-c99/src/Copilot/Compile/C99/Type.hs
index f94dbac6..78777617 100644
--- a/copilot-c99/src/Copilot/Compile/C99/Type.hs
+++ b/copilot-c99/src/Copilot/Compile/C99/Type.hs
@@ -12,7 +12,7 @@ module Copilot.Compile.C99.Type
 import qualified Language.C99.Simple as C
 
 -- Internal imports: Copilot
-import Copilot.Core ( Type (..), tylength, typename )
+import Copilot.Core ( Type (..), typeLength, typeName )
 
 -- | Translate a Copilot type to a C99 type.
 transType :: Type a -> C.Type
@@ -30,8 +30,8 @@ transType ty = case ty of
   Double    -> C.TypeSpec C.Double
   Array ty' -> C.Array (transType ty') len
     where
-      len = Just $ C.LitInt $ fromIntegral $ tylength ty
-  Struct s  -> C.TypeSpec $ C.Struct (typename s)
+      len = Just $ C.LitInt $ fromIntegral $ typeLength ty
+  Struct s  -> C.TypeSpec $ C.Struct (typeName s)
 
 -- | Translate a Copilot type to a valid (local) variable declaration C99 type.
 --
diff --git a/copilot-c99/tests/Test/Copilot/Compile/C99.hs b/copilot-c99/tests/Test/Copilot/Compile/C99.hs
index 2c98bb85..dfca1780 100644
--- a/copilot-c99/tests/Test/Copilot/Compile/C99.hs
+++ b/copilot-c99/tests/Test/Copilot/Compile/C99.hs
@@ -279,7 +279,7 @@ arbitraryArrayIx :: forall t n . (Typed t, KnownNat n, Num t)
                         , [Array n t] -> [Word32] -> [t]
                         )
 arbitraryArrayIx = return
-  (Op2 (Index typeOf), zipWith (\x y -> arrayelems x !! fromIntegral y))
+  (Op2 (Index typeOf), zipWith (\x y -> arrayElems x !! fromIntegral y))
 
 -- | Generator of functions on Floating point numbers.
 arbitraryOpFloat :: (Floating t, Typed t) => Gen (Fun t t, [t] -> [t])
@@ -860,7 +860,7 @@ varDeclC Word64       v = "uint64_t " ++ v
 varDeclC Float        v = "float " ++ v
 varDeclC Double       v = "double " ++ v
 varDeclC t@(Array tE) v =
-  typeC tE ++ " " ++ v ++ "[" ++ show (tylength t) ++ "]"
+  typeC tE ++ " " ++ v ++ "[" ++ show (typeLength t) ++ "]"
 varDeclC _            _ = error
   "copilot-c99 (test): Input variables of type struct are not yet supported."
 
@@ -877,7 +877,7 @@ sizeC Word32       = "sizeof(uint32_t)"
 sizeC Word64       = "sizeof(uint64_t)"
 sizeC Float        = "sizeof(float)"
 sizeC Double       = "sizeof(double)"
-sizeC t@(Array tE) = show (tylength t) ++ "* sizeof(" ++ typeC tE ++ ")"
+sizeC t@(Array tE) = show (typeLength t) ++ "* sizeof(" ++ typeC tE ++ ")"
 sizeC _            = error
   "copilot-c99 (test): Input variables of type struct are not yet supported."
 
@@ -920,7 +920,7 @@ instance CShow Bool where
   cshow False = "false"
 
 instance CShow t => CShow (Array n t) where
-  cshow a = intercalate "," $ map cshow $ arrayelems a
+  cshow a = intercalate "," $ map cshow $ arrayElems a
 
 -- | Read a value of a given type in C.
 class ReadableFromC a where
diff --git a/copilot-core/CHANGELOG b/copilot-core/CHANGELOG
index 492963d4..cf836f04 100644
--- a/copilot-core/CHANGELOG
+++ b/copilot-core/CHANGELOG
@@ -1,3 +1,6 @@
+2023-11-05
+        * Compliance with style guide. (#457)
+
 2023-09-07
         * Version bump (3.16.1). (#455)
 
diff --git a/copilot-core/src/Copilot/Core/Type.hs b/copilot-core/src/Copilot/Core/Type.hs
index 9a390806..3da6917d 100644
--- a/copilot-core/src/Copilot/Core/Type.hs
+++ b/copilot-core/src/Copilot/Core/Type.hs
@@ -23,16 +23,21 @@ module Copilot.Core.Type
     , UType (..)
     , SimpleType (..)
 
+    , typeSize
     , tysize
+    , typeLength
     , tylength
 
     , Value (..)
     , toValues
     , Field (..)
+    , typeName
     , typename
 
     , Struct
+    , fieldName
     , fieldname
+    , accessorName
     , accessorname
     )
   where
@@ -50,11 +55,19 @@ import GHC.TypeLits       (KnownNat, KnownSymbol, Symbol, natVal, sameNat,
 -- Internal imports
 import Copilot.Core.Type.Array (Array)
 
+{-# DEPRECATED typename "Use typeName instead." #-}
+
 -- | The value of that is a product or struct, defined as a constructor with
 -- several fields.
 class Struct a where
+  -- | Returns the name of struct in the target language.
+  typeName :: a -> String
+  typeName = typename
+
   -- | Returns the name of struct in the target language.
   typename :: a -> String
+  typename = typeName
+
   -- | Transforms all the struct's fields into a list of values.
   toValues :: a -> [Value a]
 
@@ -66,18 +79,30 @@ data Value a =
 -- level.
 data Field (s :: Symbol) t = Field t
 
+-- | Extract the name of a field.
+fieldName :: forall s t . KnownSymbol s => Field s t -> String
+fieldName _ = symbolVal (Proxy :: Proxy s)
+
+{-# DEPRECATED fieldname "Use fieldName instead." #-}
 -- | Extract the name of a field.
 fieldname :: forall s t . KnownSymbol s => Field s t -> String
-fieldname _ = symbolVal (Proxy :: Proxy s)
+fieldname = fieldName
+
+-- | Extract the name of an accessor (a function that returns a field of a
+-- struct).
+accessorName :: forall a s t . (Struct a, KnownSymbol s)
+             => (a -> Field s t) -> String
+accessorName _ = symbolVal (Proxy :: Proxy s)
 
+{-# DEPRECATED accessorname "Use accessorName instead." #-}
 -- | Extract the name of an accessor (a function that returns a field of a
 -- struct).
 accessorname :: forall a s t . (Struct a, KnownSymbol s)
              => (a -> Field s t) -> String
-accessorname _ = symbolVal (Proxy :: Proxy s)
+accessorname = accessorName
 
 instance (KnownSymbol s, Show t) => Show (Field s t) where
-  show f@(Field v) = fieldname f ++ ":" ++ show v
+  show f@(Field v) = fieldName f ++ ":" ++ show v
 
 instance {-# OVERLAPPABLE #-} (Typed t, Struct t) => Show t where
   show t = "<" ++ fields ++ ">"
@@ -108,14 +133,24 @@ data Type :: * -> * where
                          ) => Type t -> Type (Array n t)
   Struct :: (Typed a, Struct a) => a -> Type a
 
+-- | Return the length of an array from its type
+typeLength :: forall n t . KnownNat n => Type (Array n t) -> Int
+typeLength _ = fromIntegral $ natVal (Proxy :: Proxy n)
+
+{-# DEPRECATED tylength "Use typeLength instead." #-}
 -- | Return the length of an array from its type
 tylength :: forall n t . KnownNat n => Type (Array n t) -> Int
-tylength _ = fromIntegral $ natVal (Proxy :: Proxy n)
+tylength = typeLength
+
+-- | Return the total (nested) size of an array from its type
+typeSize :: forall n t . KnownNat n => Type (Array n t) -> Int
+typeSize ty@(Array ty'@(Array _)) = typeLength ty * typeSize ty'
+typeSize ty@(Array _            ) = typeLength ty
 
+{-# DEPRECATED tysize "Use typeSize instead." #-}
 -- | Return the total (nested) size of an array from its type
 tysize :: forall n t . KnownNat n => Type (Array n t) -> Int
-tysize ty@(Array ty'@(Array _)) = tylength ty * tysize ty'
-tysize ty@(Array _            ) = tylength ty
+tysize = typeSize
 
 instance TestEquality Type where
   testEquality Bool   Bool   = Just DE.Refl
diff --git a/copilot-core/src/Copilot/Core/Type/Array.hs b/copilot-core/src/Copilot/Core/Type/Array.hs
index 5f0995b2..2bca9bc1 100644
--- a/copilot-core/src/Copilot/Core/Type/Array.hs
+++ b/copilot-core/src/Copilot/Core/Type/Array.hs
@@ -13,6 +13,7 @@
 module Copilot.Core.Type.Array
     ( Array
     , array
+    , arrayElems
     , arrayelems
     )
   where
@@ -39,6 +40,11 @@ array xs | datalen == typelen = Array xs
     errmsg = "Length of data (" ++ show datalen ++
              ") does not match length of type (" ++ show typelen ++ ")."
 
+-- | Return the elements of an array.
+arrayElems :: Array n a -> [a]
+arrayElems (Array xs) = xs
+
+{-# DEPRECATED arrayelems "Use ArrayElems instead." #-}
 -- | Return the elemts of an array.
 arrayelems :: Array n a -> [a]
-arrayelems (Array xs) = xs
+arrayelems = arrayElems
diff --git a/copilot-core/tests/Test/Copilot/Core/Type/Array.hs b/copilot-core/tests/Test/Copilot/Core/Type/Array.hs
index 4a0f0f52..9a98d49c 100644
--- a/copilot-core/tests/Test/Copilot/Core/Type/Array.hs
+++ b/copilot-core/tests/Test/Copilot/Core/Type/Array.hs
@@ -13,7 +13,7 @@ import Test.QuickCheck                      (Gen, Property, arbitrary, forAll,
                                              vectorOf)
 
 -- Internal imports: library modules being tested
-import Copilot.Core.Type.Array (Array, array, arrayelems)
+import Copilot.Core.Type.Array (Array, array, arrayElems)
 
 -- | All unit tests for copilot-core:Copilot.Core.Array.
 tests :: Test.Framework.Test
@@ -30,13 +30,13 @@ tests =
 -- * Individual tests
 
 -- | Test that building an array from a list and extracting the elements with
--- the function 'arrayelems' will result in the same list.
+-- the function 'arrayElems' will result in the same list.
 testArrayElemsLeft :: forall n . KnownNat n => Proxy n -> Property
 testArrayElemsLeft len =
     forAll xsInt64 $ \ls ->
       let array' :: Array n Int64
           array' = array ls
-      in arrayelems array' == ls
+      in arrayElems array' == ls
 
   where
 
diff --git a/copilot-interpreter/CHANGELOG b/copilot-interpreter/CHANGELOG
index 16411d43..b4bbd09f 100644
--- a/copilot-interpreter/CHANGELOG
+++ b/copilot-interpreter/CHANGELOG
@@ -1,3 +1,6 @@
+2023-11-05
+        * Replace uses of deprecated functions. (#457)
+
 2023-09-07
         * Version bump (3.16.1). (#455)
 
diff --git a/copilot-interpreter/src/Copilot/Interpret/Eval.hs b/copilot-interpreter/src/Copilot/Interpret/Eval.hs
index 19d7e61d..a0083524 100644
--- a/copilot-interpreter/src/Copilot/Interpret/Eval.hs
+++ b/copilot-interpreter/src/Copilot/Interpret/Eval.hs
@@ -17,7 +17,7 @@ module Copilot.Interpret.Eval
 
 import Copilot.Core            (Expr (..), Field (..), Id, Name, Observer (..),
                                 Op1 (..), Op2 (..), Op3 (..), Spec, Stream (..),
-                                Trigger (..), Type (..), UExpr (..), arrayelems,
+                                Trigger (..), Type (..), UExpr (..), arrayElems,
                                 specObservers, specStreams, specTriggers)
 import Copilot.Interpret.Error (badUsage)
 
@@ -242,7 +242,7 @@ evalOp2 op = case op of
   BwXor _      -> (xor)
   BwShiftL _ _ -> ( \ !a !b -> shiftL a $! fromIntegral b )
   BwShiftR _ _ -> ( \ !a !b -> shiftR a $! fromIntegral b )
-  Index    _   -> \xs n -> (arrayelems xs) !! (fromIntegral n)
+  Index    _   -> \xs n -> (arrayElems xs) !! (fromIntegral n)
 
 -- | Apply a function to two numbers, so long as the second one is
 -- not zero.
diff --git a/copilot-prettyprinter/CHANGELOG b/copilot-prettyprinter/CHANGELOG
index 4bb2d40e..c982374b 100644
--- a/copilot-prettyprinter/CHANGELOG
+++ b/copilot-prettyprinter/CHANGELOG
@@ -1,3 +1,6 @@
+2023-11-05
+        * Replace uses of deprecated functions. (#457)
+
 2023-09-07
         * Version bump (3.16.1). (#455)
 
diff --git a/copilot-prettyprinter/src/Copilot/PrettyPrint.hs b/copilot-prettyprinter/src/Copilot/PrettyPrint.hs
index 10100a88..88734682 100644
--- a/copilot-prettyprinter/src/Copilot/PrettyPrint.hs
+++ b/copilot-prettyprinter/src/Copilot/PrettyPrint.hs
@@ -71,7 +71,7 @@ ppOp1 op = case op of
   Floor _                 -> ppPrefix "floor"
   BwNot _                 -> ppPrefix "~"
   Cast _ _                -> ppPrefix "(cast)"
-  GetField (Struct _) _ f -> \e -> ppInfix "#" e (text $ accessorname f)
+  GetField (Struct _) _ f -> \e -> ppInfix "#" e (text $ accessorName f)
   GetField _ _ _          -> impossible "ppOp1" "Copilot.PrettyPrint"
 
 -- | Pretty-print a binary operation.
diff --git a/copilot-theorem/CHANGELOG b/copilot-theorem/CHANGELOG
index 867ce149..be9e693f 100644
--- a/copilot-theorem/CHANGELOG
+++ b/copilot-theorem/CHANGELOG
@@ -1,5 +1,6 @@
-2023-11-03
+2023-11-05
         * Relax version constraint on what4. (#461)
+        * Replace uses of deprecated functions. (#457)
 
 2023-09-07
         * Version bump (3.16.1). (#455)
diff --git a/copilot-theorem/src/Copilot/Theorem/What4/Translate.hs b/copilot-theorem/src/Copilot/Theorem/What4/Translate.hs
index 12803375..f55e3884 100644
--- a/copilot-theorem/src/Copilot/Theorem/What4/Translate.hs
+++ b/copilot-theorem/src/Copilot/Theorem/What4/Translate.hs
@@ -365,7 +365,7 @@ translateConstExpr sym tp a = case tp of
   CT.Float -> XFloat <$> WFP.iFloatLitSingle sym a
   CT.Double -> XDouble <$> WFP.iFloatLitDouble sym a
   CT.Array tp -> do
-    elts <- traverse (translateConstExpr sym tp) (CT.arrayelems a)
+    elts <- traverse (translateConstExpr sym tp) (CT.arrayElems a)
     Some n <- return $ mkNatRepr (genericLength elts)
     case isZeroOrGT1 n of
       Left Refl -> return XEmptyArray
diff --git a/copilot/CHANGELOG b/copilot/CHANGELOG
index 74185c53..b3764b01 100644
--- a/copilot/CHANGELOG
+++ b/copilot/CHANGELOG
@@ -1,3 +1,6 @@
+2023-11-05
+        * Replace uses of deprecated functions. (#457)
+
 2023-11-03
         * Fix typo in README. (#459)
 
diff --git a/copilot/examples/Structs.hs b/copilot/examples/Structs.hs
index f826585a..f3b83b1f 100644
--- a/copilot/examples/Structs.hs
+++ b/copilot/examples/Structs.hs
@@ -19,7 +19,7 @@ data Volts = Volts
 
 -- | `Struct` instance for `Volts`.
 instance Struct Volts where
-  typename _ = "volts"
+  typeName _ = "volts"
   toValues volts = [ Value Word16 (numVolts volts)
                    , Value Bool   (flag volts)
                    ]
@@ -36,7 +36,7 @@ data Battery = Battery
 
 -- | `Battery` instance for `Struct`.
 instance Struct Battery where
-  typename _ = "battery"
+  typeName _ = "battery"
   toValues battery = [ Value typeOf (temp battery)
                      , Value typeOf (volts battery)
                      , Value typeOf (other battery)
diff --git a/copilot/examples/what4/Structs.hs b/copilot/examples/what4/Structs.hs
index 413bc454..ff44ec25 100644
--- a/copilot/examples/what4/Structs.hs
+++ b/copilot/examples/what4/Structs.hs
@@ -20,7 +20,7 @@ data Volts = Volts
 
 -- | `Struct` instance for `Volts`.
 instance Struct Volts where
-  typename _ = "volts"
+  typeName _ = "volts"
   toValues volts = [ Value Word16 (numVolts volts)
                    , Value Bool   (flag volts)
                    ]
@@ -37,7 +37,7 @@ data Battery = Battery
 
 -- | `Battery` instance for `Struct`.
 instance Struct Battery where
-  typename _ = "battery"
+  typeName _ = "battery"
   toValues battery = [ Value typeOf (temp battery)
                      , Value typeOf (volts battery)
                      , Value typeOf (other battery)