diff --git a/lib/customisation.nix b/lib/customisation.nix
index fe32e890f357..a9281b1ab698 100644
--- a/lib/customisation.nix
+++ b/lib/customisation.nix
@@ -46,12 +46,6 @@ rec {
       //
       (drv.passthru or {})
       //
-      # TODO(@Artturin): remove before release 23.05 and only have __spliced.
-      (lib.optionalAttrs (drv ? crossDrv && drv ? nativeDrv) {
-        crossDrv = overrideDerivation drv.crossDrv f;
-        nativeDrv = overrideDerivation drv.nativeDrv f;
-      })
-      //
       lib.optionalAttrs (drv ? __spliced) {
         __spliced = {} // (lib.mapAttrs (_: sDrv: overrideDerivation sDrv f) drv.__spliced);
       });
diff --git a/pkgs/stdenv/generic/make-derivation.nix b/pkgs/stdenv/generic/make-derivation.nix
index e96fa68ba0c2..232ba2f8a8ac 100644
--- a/pkgs/stdenv/generic/make-derivation.nix
+++ b/pkgs/stdenv/generic/make-derivation.nix
@@ -359,57 +359,31 @@ else let
 
       # This parameter is sometimes a string, sometimes null, and sometimes a list, yuck
       configureFlags = let inherit (lib) optional elem; in
-        (/**/ if lib.isString configureFlags then lib.warn "String 'configureFlags' is deprecated and will be removed in release 23.05. Please use a list of strings. Derivation name: ${derivationArg.name}, file: ${pos.file or "unknown file"}" [configureFlags]
-         else if configureFlags == null      then lib.warn "Null 'configureFlags' is deprecated and will be removed in release 23.05. Please use a empty list instead '[]'. Derivation name: ${derivationArg.name}, file: ${pos.file or "unknown file"}" []
-         else                                     configureFlags)
+        configureFlags
         ++ optional (elem "build"  configurePlatforms) "--build=${stdenv.buildPlatform.config}"
         ++ optional (elem "host"   configurePlatforms) "--host=${stdenv.hostPlatform.config}"
         ++ optional (elem "target" configurePlatforms) "--target=${stdenv.targetPlatform.config}";
 
       cmakeFlags =
-        let
-          explicitFlags =
-            if lib.isString cmakeFlags then lib.warn
-                "String 'cmakeFlags' is deprecated and will be removed in release 23.05. Please use a list of strings. Derivation name: ${derivationArg.name}, file: ${pos.file or "unknown file"}"
-                [cmakeFlags]
-            else if cmakeFlags == null then
-              lib.warn
-                "Null 'cmakeFlags' is deprecated and will be removed in release 23.05. Please use a empty list instead '[]'. Derivation name: ${derivationArg.name}, file: ${pos.file or "unknown file"}"
-                []
-            else
-              cmakeFlags;
-
-          crossFlags = [
-            "-DCMAKE_SYSTEM_NAME=${lib.findFirst lib.isString "Generic" (lib.optional (!stdenv.hostPlatform.isRedox) stdenv.hostPlatform.uname.system)}"
-          ] ++ lib.optionals (stdenv.hostPlatform.uname.processor != null) [
-            "-DCMAKE_SYSTEM_PROCESSOR=${stdenv.hostPlatform.uname.processor}"
-          ] ++ lib.optionals (stdenv.hostPlatform.uname.release != null) [
-            "-DCMAKE_SYSTEM_VERSION=${stdenv.hostPlatform.uname.release}"
-          ] ++ lib.optionals (stdenv.hostPlatform.isDarwin) [
-            "-DCMAKE_OSX_ARCHITECTURES=${stdenv.hostPlatform.darwinArch}"
-          ] ++ lib.optionals (stdenv.buildPlatform.uname.system != null) [
-            "-DCMAKE_HOST_SYSTEM_NAME=${stdenv.buildPlatform.uname.system}"
-          ] ++ lib.optionals (stdenv.buildPlatform.uname.processor != null) [
-            "-DCMAKE_HOST_SYSTEM_PROCESSOR=${stdenv.buildPlatform.uname.processor}"
-          ] ++ lib.optionals (stdenv.buildPlatform.uname.release != null) [
-            "-DCMAKE_HOST_SYSTEM_VERSION=${stdenv.buildPlatform.uname.release}"
-          ];
-        in
-          explicitFlags ++ lib.optionals (stdenv.hostPlatform != stdenv.buildPlatform) crossFlags;
+        cmakeFlags
+        ++ lib.optionals (stdenv.hostPlatform != stdenv.buildPlatform) ([
+          "-DCMAKE_SYSTEM_NAME=${lib.findFirst lib.isString "Generic" (lib.optional (!stdenv.hostPlatform.isRedox) stdenv.hostPlatform.uname.system)}"
+        ] ++ lib.optionals (stdenv.hostPlatform.uname.processor != null) [
+          "-DCMAKE_SYSTEM_PROCESSOR=${stdenv.hostPlatform.uname.processor}"
+        ] ++ lib.optionals (stdenv.hostPlatform.uname.release != null) [
+          "-DCMAKE_SYSTEM_VERSION=${stdenv.hostPlatform.uname.release}"
+        ] ++ lib.optionals (stdenv.hostPlatform.isDarwin) [
+          "-DCMAKE_OSX_ARCHITECTURES=${stdenv.hostPlatform.darwinArch}"
+        ] ++ lib.optionals (stdenv.buildPlatform.uname.system != null) [
+          "-DCMAKE_HOST_SYSTEM_NAME=${stdenv.buildPlatform.uname.system}"
+        ] ++ lib.optionals (stdenv.buildPlatform.uname.processor != null) [
+          "-DCMAKE_HOST_SYSTEM_PROCESSOR=${stdenv.buildPlatform.uname.processor}"
+        ] ++ lib.optionals (stdenv.buildPlatform.uname.release != null) [
+          "-DCMAKE_HOST_SYSTEM_VERSION=${stdenv.buildPlatform.uname.release}"
+        ]);
 
       mesonFlags =
         let
-          explicitFlags =
-            if lib.isString mesonFlags then lib.warn
-                "String 'mesonFlags' is deprecated and will be removed in release 23.05. Please use a list of strings. Derivation name: ${derivationArg.name}, file: ${pos.file or "unknown file"}"
-                [mesonFlags]
-            else if mesonFlags == null then
-              lib.warn
-                "Null 'mesonFlags' is deprecated and will be removed in release 23.05. Please use a empty list instead '[]'. Derivation name: ${derivationArg.name}, file: ${pos.file or "unknown file"}"
-                []
-            else
-              mesonFlags;
-
           # See https://mesonbuild.com/Reference-tables.html#cpu-families
           cpuFamily = platform: with platform;
             /**/ if isAarch32 then "arm"
@@ -430,7 +404,7 @@ else let
             llvm-config = 'llvm-config-native'
           '';
           crossFlags = lib.optionals (stdenv.hostPlatform != stdenv.buildPlatform) [ "--cross-file=${crossFile}" ];
-        in crossFlags ++ explicitFlags;
+        in crossFlags ++ mesonFlags;
 
       inherit patches;
 
diff --git a/pkgs/top-level/splice.nix b/pkgs/top-level/splice.nix
index ce536aa1fd2f..0a138947e8da 100644
--- a/pkgs/top-level/splice.nix
+++ b/pkgs/top-level/splice.nix
@@ -45,9 +45,6 @@ let
             valueHostTarget = pkgsHostTarget.${name} or { };
             valueTargetTarget = pkgsTargetTarget.${name} or { };
             augmentedValue = defaultValue
-              # TODO(@Artturin): remove before release 23.05 and only have __spliced.
-              // (lib.optionalAttrs (pkgsBuildHost ? ${name}) { nativeDrv = lib.warn "use ${name}.__spliced.buildHost instead of ${name}.nativeDrv" valueBuildHost; })
-              // (lib.optionalAttrs (pkgsHostTarget ? ${name}) { crossDrv = lib.warn "use ${name}.__spliced.hostTarget instead of ${name}.crossDrv" valueHostTarget; })
               // {
               __spliced =
                 (lib.optionalAttrs (pkgsBuildBuild ? ${name}) { buildBuild = valueBuildBuild; })