diff --git a/.gitignore b/.gitignore
index 7b872195880..cd9499f6c1a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -19,6 +19,7 @@
 /windows/src/**/*.identcache
 /windows/src/**/*.vcxproj.user
 /windows/src/**/version.res
+/windows/src/**/version*.res
 /windows/src/**/*.pch
 /windows/src/**/*.wixobj
 /windows/src/**/*.sbr
@@ -186,3 +187,6 @@ lcov.info
 
 # flag file for build script
 .configured
+
+# Meson wrap dependency lock files
+**/subprojects/.wraplock
diff --git a/common/windows/delphi/components/FixedTrackbar.pas b/common/windows/delphi/components/FixedTrackbar.pas
index 50cb444a55f..8d3c525d842 100644
--- a/common/windows/delphi/components/FixedTrackbar.pas
+++ b/common/windows/delphi/components/FixedTrackbar.pas
@@ -70,10 +70,14 @@ procedure TTntFixedDrawGrid.WMEraseBkgnd(var Message: TMessage);
 {$MESSAGE WARN 'Not yet checked against Delphi 10.4'}
 {$IFNDEF VER330}
 {$IFNDEF VER320}
+{$IFNDEF VER350}
+{$IFNDEF VER360}
 {$MESSAGE ERROR 'Check that this fix is still applicable for a new version of Delphi. Checked against Delphi 10.2, 10.3' }
 {$ENDIF}
 {$ENDIF}
 {$ENDIF}
+{$ENDIF}
+{$ENDIF}
 
 procedure TTntFixedDrawGrid.MouseDown(Button: TMouseButton;
   Shift: TShiftState; X, Y: Integer);
diff --git a/common/windows/delphi/general/CleartypeDrawCharacter.pas b/common/windows/delphi/general/CleartypeDrawCharacter.pas
index 6d1a51976de..44562012ed2 100644
--- a/common/windows/delphi/general/CleartypeDrawCharacter.pas
+++ b/common/windows/delphi/general/CleartypeDrawCharacter.pas
@@ -591,11 +591,11 @@ function TestFont(FFontName: string): Boolean;
   StrPCopy(lf.lfFaceName, FFontName); //'Code2000');
   hdc := GetDC(0);
   //FPlane0FontName := 'Code2000';
-{$IFDEF VER340}
+{$IF Defined(VER340) or Defined(VER350) or Defined(VER360)}
   if EnumFontFamiliesEx(hdc, lf, @EnumFallbackFonts, 0, 0) <> 0 then
 {$ELSE}
   if EnumFontFamiliesEx(hdc, lf, @EnumFallbackFonts, 0, 0) then
-{$ENDIF}
+{$IFEND}
   begin
     FPlane0FontName := FFontName;
     Result := True;
diff --git a/common/windows/delphi/general/JsonUtil.pas b/common/windows/delphi/general/JsonUtil.pas
index ae2b9b0e9c6..16a90bc729d 100644
--- a/common/windows/delphi/general/JsonUtil.pas
+++ b/common/windows/delphi/general/JsonUtil.pas
@@ -52,7 +52,11 @@ function JSONToString(obj: TJSONAncestor; ReplaceSlashes: Boolean = False): stri
   begin
     builder := TStringBuilder.Create;
     try
+{$IF Defined(VER350) or Defined(VER360)}
+      obj.ToChars(builder, []);
+{$ELSE}
       obj.ToChars(builder);
+{$IFEND}
       Result := builder.ToString;
     finally
       builder.Free;
diff --git a/common/windows/delphi/tools/devtools/SourceRootPath.pas b/common/windows/delphi/tools/devtools/SourceRootPath.pas
index 360477641e7..c8372c3c6e2 100644
--- a/common/windows/delphi/tools/devtools/SourceRootPath.pas
+++ b/common/windows/delphi/tools/devtools/SourceRootPath.pas
@@ -14,11 +14,19 @@ interface
 {$IFDEF VER340}
 const DelphiMajorVersion = '21.0';
 {$ELSE}
+{$IFDEF VER350}
+const DelphiMajorVersion = '22.0';
+{$ELSE}
+{$IFDEF VER360}
+const DelphiMajorVersion = '23.0';
+{$ELSE}
 ERROR: must define Delphi version
 {$ENDIF}
 {$ENDIF}
 {$ENDIF}
 {$ENDIF}
+{$ENDIF}
+{$ENDIF}
 
 const DelphiBasePath = 'C:\Program Files (x86)\Embarcadero\Studio\' + DelphiMajorVersion + '\';
 
diff --git a/common/windows/delphi/web/Keyman.System.HttpServer.Base.pas b/common/windows/delphi/web/Keyman.System.HttpServer.Base.pas
index d1daf087c39..8df4e732056 100644
--- a/common/windows/delphi/web/Keyman.System.HttpServer.Base.pas
+++ b/common/windows/delphi/web/Keyman.System.HttpServer.Base.pas
@@ -46,7 +46,13 @@ function CrackUTF8ZeroExtendedString(CommandType: THTTPCommandType; const p: str
   // Indy's UTF8 handling of URLs is *completely* broken.
   // We may need to check this with updated versions of Delphi
 {$IFNDEF VER330}
+{$IFNDEF VER340}
+{$IFNDEF VER350}
+{$IFNDEF VER360}
   ERROR! Check if this is still needed with Delphi update
+{$ENDIF}
+{$ENDIF}
+{$ENDIF}
 {$ENDIF}
 
   SetLength(s, p.Length);
diff --git a/developer/src/ext/jedi/jcl/jcl/source/common/JclSynch.pas b/developer/src/ext/jedi/jcl/jcl/source/common/JclSynch.pas
index f73b1722b09..eb405224249 100644
--- a/developer/src/ext/jedi/jcl/jcl/source/common/JclSynch.pas
+++ b/developer/src/ext/jedi/jcl/jcl/source/common/JclSynch.pas
@@ -937,11 +937,15 @@ function TJclCriticalSectionEx.TryEnter: Boolean;
 
 //== { TJclEvent } ===========================================================
 
+// Keyman local patch: Delphi 11/12 compat (vendored JCL). Explicit BOOL() casts
+// added below to satisfy Delphi 12's stricter implicit-Boolean->BOOL conversion.
+// Backwards-compatible with Delphi 10.3 (BOOL is an ordinal-preserving typecast).
+// On JCL refresh from upstream: re-apply if upstream hasn't picked up the cast.
 constructor TJclEvent.Create(SecAttr: PSecurityAttributes; Manual, Signaled: Boolean; const Name: string);
 begin
   inherited Create;
   FName := Name;
-  FHandle := {$IFDEF HAS_UNITSCOPE}Winapi.{$ENDIF}Windows.CreateEvent(SecAttr, Manual, Signaled, PChar(FName));
+  FHandle := {$IFDEF HAS_UNITSCOPE}Winapi.{$ENDIF}Windows.CreateEvent(SecAttr, BOOL(Manual), BOOL(Signaled), PChar(FName));
   if FHandle = 0 then
     raise EJclEventError.CreateRes(@RsSynchCreateEvent);
   FExisted := GetLastError = ERROR_ALREADY_EXISTS;
@@ -952,7 +956,7 @@ constructor TJclEvent.Open(Access: Cardinal; Inheritable: Boolean;
 begin
   FName := Name;
   FExisted := True;
-  FHandle := {$IFDEF HAS_UNITSCOPE}Winapi.{$ENDIF}Windows.OpenEvent(Access, Inheritable, PChar(Name));
+  FHandle := {$IFDEF HAS_UNITSCOPE}Winapi.{$ENDIF}Windows.OpenEvent(Access, BOOL(Inheritable), PChar(Name));
   if FHandle = 0 then
     raise EJclEventError.CreateRes(@RsSynchOpenEvent);
 end;
@@ -980,7 +984,7 @@ constructor TJclWaitableTimer.Create(SecAttr: PSecurityAttributes;
 begin
   FName := Name;
   FResume := False;
-  FHandle := CreateWaitableTimer(SecAttr, Manual, PChar(Name));
+  FHandle := CreateWaitableTimer(SecAttr, BOOL(Manual), PChar(Name));
   if FHandle = 0 then
     raise EJclWaitableTimerError.CreateRes(@RsSynchCreateWaitableTimer);
   FExisted := GetLastError = ERROR_ALREADY_EXISTS;
@@ -1000,7 +1004,7 @@ constructor TJclWaitableTimer.Open(Access: Cardinal; Inheritable: Boolean;
   FExisted := True;
   FName := Name;
   FResume := False;
-  FHandle := OpenWaitableTimer(Access, Inheritable, PChar(Name));
+  FHandle := OpenWaitableTimer(Access, BOOL(Inheritable), PChar(Name));
   if FHandle = 0 then
     raise EJclWaitableTimerError.CreateRes(@RsSynchOpenWaitableTimer);
 end;
@@ -1048,7 +1052,7 @@ constructor TJclSemaphore.Open(Access: Cardinal; Inheritable: Boolean;
 begin
   FName := Name;
   FExisted := True;
-  FHandle := {$IFDEF HAS_UNITSCOPE}Winapi.{$ENDIF}Windows.OpenSemaphore(Access, Inheritable, PChar(Name));
+  FHandle := {$IFDEF HAS_UNITSCOPE}Winapi.{$ENDIF}Windows.OpenSemaphore(Access, BOOL(Inheritable), PChar(Name));
   if FHandle = 0 then
     raise EJclSemaphoreError.CreateRes(@RsSynchOpenSemaphore);
 end;
@@ -1075,7 +1079,7 @@ constructor TJclMutex.Create(SecAttr: PSecurityAttributes; InitialOwner: Boolean
 begin
   inherited Create;
   FName := Name;
-  FHandle := JclWin32.CreateMutex(SecAttr, InitialOwner, PChar(Name));
+  FHandle := {$IFDEF HAS_UNITSCOPE}Winapi.{$ENDIF}Windows.CreateMutex(SecAttr, BOOL(InitialOwner), PChar(Name));
   if FHandle = 0 then
     raise EJclMutexError.CreateRes(@RsSynchCreateMutex);
   FExisted := GetLastError = ERROR_ALREADY_EXISTS;
@@ -1086,7 +1090,7 @@ constructor TJclMutex.Open(Access: Cardinal; Inheritable: Boolean; const Name: s
   inherited Create;
   FName := Name;
   FExisted := True;
-  FHandle := {$IFDEF HAS_UNITSCOPE}Winapi.{$ENDIF}Windows.OpenMutex(Access, Inheritable, PChar(Name));
+  FHandle := {$IFDEF HAS_UNITSCOPE}Winapi.{$ENDIF}Windows.OpenMutex(Access, BOOL(Inheritable), PChar(Name));
   if FHandle = 0 then
     raise EJclMutexError.CreateRes(@RsSynchOpenMutex);
 end;
diff --git a/developer/src/ext/jedi/jvcl/jvcl/run/JvComponent.pas b/developer/src/ext/jedi/jvcl/jvcl/run/JvComponent.pas
index 1877ee48efe..fab8609e2c8 100644
--- a/developer/src/ext/jedi/jvcl/jvcl/run/JvComponent.pas
+++ b/developer/src/ext/jedi/jvcl/jvcl/run/JvComponent.pas
@@ -123,8 +123,16 @@ constructor TJvForm.Create(AOwner: TComponent);
       finally
         Exclude(FFormState, fsCreating);
       end;
+      // Keyman local patch: Delphi 11/12 compat (vendored JVCL). The
+      // OldCreateOrder property was removed in Delphi 11; the modern semantics
+      // are equivalent to OldCreateOrder=True, so always call DoCreate on
+      // VER350+. On JVCL refresh from upstream: re-apply if not yet upstreamed.
+{$IF Defined(VER350) or Defined(VER360)}
+      DoCreate;
+{$ELSE}
       if OldCreateOrder then
         DoCreate;
+{$IFEND}
     end;
   finally
     GlobalNameSpace.EndWrite;
diff --git a/developer/src/ext/mbcolor/mxs.inc b/developer/src/ext/mbcolor/mxs.inc
index 41b82ad96e5..75ca0b34e73 100644
--- a/developer/src/ext/mbcolor/mxs.inc
+++ b/developer/src/ext/mbcolor/mxs.inc
@@ -7,6 +7,28 @@
      {$define DELPHI_10_UP}
     {$endif}
 
+    // Keyman local patch: Delphi 11/12 compat (vendored mbcolor). Without
+    // these blocks DELPHI_*_UP flags are never defined on VER350/VER360,
+    // which causes HTMLColors.pas to drop "uses Variants" and fail to
+    // resolve the Null constant. On mbcolor refresh: re-apply if needed.
+    {$ifdef VER350}
+     {$define DELPHI_5_UP}
+     {$define DELPHI_6_UP}
+     {$define DELPHI_7_UP}
+     {$define DELPHI_8_UP}
+     {$define DELPHI_9_UP}
+     {$define DELPHI_10_UP}
+    {$endif}
+
+    {$ifdef VER360}
+     {$define DELPHI_5_UP}
+     {$define DELPHI_6_UP}
+     {$define DELPHI_7_UP}
+     {$define DELPHI_8_UP}
+     {$define DELPHI_9_UP}
+     {$define DELPHI_10_UP}
+    {$endif}
+
     {$ifdef VER330}
      {$define DELPHI_5_UP}
      {$define DELPHI_6_UP}
diff --git a/resources/build/win/configure_environment.inc.sh b/resources/build/win/configure_environment.inc.sh
index d0bce72a812..1d274c67be1 100644
--- a/resources/build/win/configure_environment.inc.sh
+++ b/resources/build/win/configure_environment.inc.sh
@@ -65,9 +65,11 @@ _build_vs_environment() {
 
 _locate_rsvars() {
   #
-  # Delphi Compiler Configuration - Delphi 10.3.2
+  # Delphi Compiler Configuration - defaults to Delphi 10.3 (BDS 20.0).
+  # Override via the KEYMAN_DELPHI_VERSION environment variable to build with
+  # a newer Delphi installation (e.g., KEYMAN_DELPHI_VERSION=23.0 for Delphi 12).
   #
-  DELPHI_VERSION=20.0
+  DELPHI_VERSION="${KEYMAN_DELPHI_VERSION:-20.0}"
   DCC32PATH="$(cygpath -u "$ProgramFilesx86\\Embarcadero\\Studio\\$DELPHI_VERSION\\bin")"
   RSVars_path="$DCC32PATH/rsvars.bat"
 }
diff --git a/resources/build/win/delphi_environment.inc.sh b/resources/build/win/delphi_environment.inc.sh
index 0465bcb6930..a68b08421c4 100644
--- a/resources/build/win/delphi_environment.inc.sh
+++ b/resources/build/win/delphi_environment.inc.sh
@@ -13,7 +13,10 @@
 DELPHIWARNINGS=(-W-MESSAGE_DIRECTIVE -W-IMPLICIT_STRING_CAST -W-IMPLICIT_STRING_CAST_LOSS -W-EXPLICIT_STRING_CAST -W-EXPLICIT_STRING_CAST_LOSS -W-CVT_WCHAR_TO_ACHAR -W-CVT_NARROWING_STRING_LOST -W-CVT_ACHAR_TO_WCHAR -W-CVT_WIDENING_STRING_LOST -W-UNICODE_TO_LOCALE -W-LOCALE_TO_UNICODE -W-IMPLICIT_VARIANTS -W-IMPLICIT_INTEGER_CAST_LOSS -W-IMPLICIT_CONVERSION_LOSS -W-COMBINING_SIGNED_UNSIGNED64 -W-COMBINING_SIGNED_UNSIGNED64)
 # !ENDIF
 
-DELPHI_VERSION=20.0
+# DELPHI_VERSION defaults to Delphi 10.3 (BDS 20.0). Override via the
+# KEYMAN_DELPHI_VERSION environment variable to build with a newer Delphi
+# installation (e.g., KEYMAN_DELPHI_VERSION=23.0 for Delphi 12).
+DELPHI_VERSION="${KEYMAN_DELPHI_VERSION:-20.0}"
 DCC32PATH="$(cygpath -u "$ProgramFilesx86\\Embarcadero\\Studio\\$DELPHI_VERSION\\bin")"
 
 source "$KEYMAN_ROOT/resources/build/win/delphi_environment_generated.inc.sh"
diff --git a/resources/builder.inc.sh b/resources/builder.inc.sh
index 6ec2fbcebff..7e9ea36a0e4 100755
--- a/resources/builder.inc.sh
+++ b/resources/builder.inc.sh
@@ -2323,7 +2323,8 @@ builder_describe_platform() {
   # Detect delphi compiler (see also delphi_environment.inc.sh)
   if builder_is_windows; then
     local ProgramFilesx86="$(cygpath -w -F 42)"
-    if [[ -x "$(cygpath -u "$ProgramFilesx86\\Embarcadero\\Studio\\20.0\\bin\\dcc32.exe")" ]]; then
+    local _delphi_version="${KEYMAN_DELPHI_VERSION:-20.0}"
+    if [[ -x "$(cygpath -u "$ProgramFilesx86\\Embarcadero\\Studio\\$_delphi_version\\bin\\dcc32.exe")" ]]; then
       builder_installed_tools+=(delphi)
     fi
   fi