diff --git a/src/sc_man_scanner.re b/src/sc_man_scanner.re
index 0dd74009a..3ef66b760 100644
--- a/src/sc_man_scanner.re
+++ b/src/sc_man_scanner.re
@@ -209,6 +209,7 @@ std2:
 		'version'					{ RET(ParseVersion >= MakeVersion(2, 4, 0)? TK_Version : TK_Identifier); }
 		'action'					{ RET(ParseVersion >= MakeVersion(1, 0, 0)? TK_Action : TK_Identifier); }
 		'readonly'					{ RET(ParseVersion >= MakeVersion(1, 0, 0)? TK_ReadOnly : TK_Identifier); }
+		'internal'					{ RET(ParseVersion >= MakeVersion(3, 4, 0)? TK_Internal : TK_Identifier); }
 		'let'						{ RET(ParseVersion >= MakeVersion(1, 0, 0)? TK_Let : TK_Identifier); }
 
 		/* Actor state options */
diff --git a/src/sc_man_tokens.h b/src/sc_man_tokens.h
index 33be1c6ae..dfe49518a 100644
--- a/src/sc_man_tokens.h
+++ b/src/sc_man_tokens.h
@@ -138,6 +138,7 @@ xx(TK_Meta,					"'meta'")
 xx(TK_Deprecated,			"'deprecated'")
 xx(TK_Version,				"'version'")
 xx(TK_ReadOnly,				"'readonly'")
+xx(TK_Internal,				"'internal'")
 
 xx(TK_CanRaise,				"'canraise'")
 xx(TK_Fast,					"'fast'")
diff --git a/src/scripting/zscript/zcc-parse.lemon b/src/scripting/zscript/zcc-parse.lemon
index 34ebd9149..11847217f 100644
--- a/src/scripting/zscript/zcc-parse.lemon
+++ b/src/scripting/zscript/zcc-parse.lemon
@@ -1120,6 +1120,7 @@ decl_flag(X) ::= FINAL(T).		{ X.Int = ZCC_Final; X.SourceLoc =  T.SourceLoc; }
 decl_flag(X) ::= META(T).		{ X.Int = ZCC_Meta; X.SourceLoc =  T.SourceLoc; }
 decl_flag(X) ::= TRANSIENT(T).	{ X.Int = ZCC_Transient; X.SourceLoc =  T.SourceLoc; }
 decl_flag(X) ::= READONLY(T).	{ X.Int = ZCC_ReadOnly; X.SourceLoc =  T.SourceLoc; }
+decl_flag(X) ::= INTERNAL(T).	{ X.Int = ZCC_Internal; X.SourceLoc =  T.SourceLoc; }
 decl_flag(X) ::= VIRTUAL(T).	{ X.Int = ZCC_Virtual; X.SourceLoc =  T.SourceLoc; }
 decl_flag(X) ::= OVERRIDE(T).	{ X.Int = ZCC_Override; X.SourceLoc =  T.SourceLoc; }
 decl_flag(X) ::= VARARG(T).     { X.Int = ZCC_VarArg; X.SourceLoc = T.SourceLoc; }
diff --git a/src/scripting/zscript/zcc_compile.cpp b/src/scripting/zscript/zcc_compile.cpp
index 1068501d6..d782383e7 100644
--- a/src/scripting/zscript/zcc_compile.cpp
+++ b/src/scripting/zscript/zcc_compile.cpp
@@ -1241,6 +1241,7 @@ bool ZCCCompiler::CompileFields(PContainerType *type, TArray<ZCC_VarDeclarator *
 		if (field->Flags & ZCC_Protected) varflags |= VARF_Protected;
 		if (field->Flags & ZCC_Deprecated) varflags |= VARF_Deprecated;
 		if (field->Flags & ZCC_ReadOnly) varflags |= VARF_ReadOnly;
+		if (field->Flags & ZCC_Internal) varflags |= VARF_InternalAccess;
 		if (field->Flags & ZCC_Transient) varflags |= VARF_Transient;
 		if (mVersion >= MakeVersion(2, 4, 0))
 		{
@@ -2327,7 +2328,7 @@ void ZCCCompiler::CompileFunction(ZCC_StructWork *c, ZCC_FuncDeclarator *f, bool
 			} while (t != f->Type);
 		}
 
-		int notallowed = ZCC_Latent | ZCC_Meta | ZCC_ReadOnly | ZCC_Abstract;
+		int notallowed = ZCC_Latent | ZCC_Meta | ZCC_ReadOnly | ZCC_Abstract | ZCC_Internal;
 
 		if (f->Flags & notallowed)
 		{
diff --git a/src/scripting/zscript/zcc_parser.cpp b/src/scripting/zscript/zcc_parser.cpp
index 6902753da..f067311ef 100644
--- a/src/scripting/zscript/zcc_parser.cpp
+++ b/src/scripting/zscript/zcc_parser.cpp
@@ -149,6 +149,7 @@ static void InitTokenMap()
 	TOKENDEF (TK_Deprecated,	ZCC_DEPRECATED);
 	TOKENDEF (TK_Version,		ZCC_VERSION);
 	TOKENDEF (TK_ReadOnly,		ZCC_READONLY);
+	TOKENDEF (TK_Internal,		ZCC_INTERNAL);
 	TOKENDEF ('{',				ZCC_LBRACE);
 	TOKENDEF ('}',				ZCC_RBRACE);
 	TOKENDEF (TK_Struct,		ZCC_STRUCT);
diff --git a/src/scripting/zscript/zcc_parser.h b/src/scripting/zscript/zcc_parser.h
index 5f0889fd2..1089b2ed8 100644
--- a/src/scripting/zscript/zcc_parser.h
+++ b/src/scripting/zscript/zcc_parser.h
@@ -63,6 +63,7 @@ enum
 	ZCC_ClearScope		= 1 << 19,
 	ZCC_VirtualScope	= 1 << 20,
 	ZCC_Version			= 1 << 21,
+	ZCC_Internal		= 1 << 22,
 };
 
 // Function parameter modifiers
diff --git a/src/version.h b/src/version.h
index afda99a21..30513f967 100644
--- a/src/version.h
+++ b/src/version.h
@@ -57,7 +57,7 @@ const char *GetVersionString();
 #define RC_PRODUCTVERSION2 VERSIONSTR
 // These are for content versioning. The current state is '3.3'.
 #define VER_MAJOR 3
-#define VER_MINOR 3
+#define VER_MINOR 4
 #define VER_REVISION 0
 
 // Version identifier for network games.
diff --git a/wadsrc/static/zscript.txt b/wadsrc/static/zscript.txt
index 31531ed28..1daf04628 100644
--- a/wadsrc/static/zscript.txt
+++ b/wadsrc/static/zscript.txt
@@ -1,4 +1,4 @@
-version "3.3"
+version "3.4"
 #include "zscript/base.txt"
 #include "zscript/sounddata.txt"
 #include "zscript/mapdata.txt"
diff --git a/wadsrc/static/zscript/mapdata.txt b/wadsrc/static/zscript/mapdata.txt
index fb62faff7..f20a9b2eb 100644
--- a/wadsrc/static/zscript/mapdata.txt
+++ b/wadsrc/static/zscript/mapdata.txt
@@ -334,7 +334,7 @@ struct Sector native play
 
 	native SectorAction		SecActTarget;
 
-	native uint					Portals[2];
+	native internal uint		Portals[2];
 	native readonly int			PortalGroup;
 
 	native readonly int			sectornum;