diff --git a/ext2sim/ext2sim.c b/ext2sim/ext2sim.c
index 6ca3dc11..af3f2d4b 100644
--- a/ext2sim/ext2sim.c
+++ b/ext2sim/ext2sim.c
@@ -210,7 +210,7 @@ Exttosim_Init(interp)
     if (interp == NULL) return TCL_ERROR;
     if (Tcl_PkgRequire(interp, "Tclmagic", MAGIC_VERSION, 0) == NULL)
 	return TCL_ERROR;
-    if (Tcl_InitStubs(interp, "8.5", 0) == NULL) return TCL_ERROR;
+    if (Tcl_InitStubs(interp, Tclmagic_InitStubsVersion, 0) == NULL) return TCL_ERROR;
 
     TxPrintf("Auto-loading EXTTOSIM module\n");
     TxFlushOut();
diff --git a/ext2spice/ext2spice.c b/ext2spice/ext2spice.c
index d7efe11a..6bc56752 100644
--- a/ext2spice/ext2spice.c
+++ b/ext2spice/ext2spice.c
@@ -208,7 +208,7 @@ Exttospice_Init(interp)
     if (interp == NULL) return TCL_ERROR;
     if (Tcl_PkgRequire(interp, "Tclmagic", MAGIC_VERSION, 0) == NULL)
 	return TCL_ERROR;
-    if (Tcl_InitStubs(interp, "8.5", 0) == NULL) return TCL_ERROR;
+    if (Tcl_InitStubs(interp, Tclmagic_InitStubsVersion, 0) == NULL) return TCL_ERROR;
 
     TxPrintf("Auto-loading EXTTOSPICE module\n");
     TxFlushOut();
diff --git a/graphics/grTCairo1.c b/graphics/grTCairo1.c
index 8cee61b1..133c518e 100644
--- a/graphics/grTCairo1.c
+++ b/graphics/grTCairo1.c
@@ -261,7 +261,7 @@ GrTCairoInit ()
 {
 	bool rstatus;
 
-	if (Tk_InitStubs(magicinterp, "8.5", 0) == NULL) return FALSE;
+	if (Tk_InitStubs(magicinterp, Tclmagic_InitStubsVersion, 0) == NULL) return FALSE;
 
 	tcairoCurrent.window = Tk_MainWindow(magicinterp);
 	if (tcairoCurrent.window == NULL)
diff --git a/graphics/grTOGL1.c b/graphics/grTOGL1.c
index bb1b0354..ec2d4c5f 100644
--- a/graphics/grTOGL1.c
+++ b/graphics/grTOGL1.c
@@ -269,7 +269,7 @@ GrTOGLInit ()
     static int attributeList[] = { GLX_RGBA, None, None };
 #endif
 
-    if (Tk_InitStubs(magicinterp, "8.5", 0) == NULL) return FALSE;
+    if (Tk_InitStubs(magicinterp, Tclmagic_InitStubsVersion, 0) == NULL) return FALSE;
 
     toglCurrent.window = Tk_MainWindow(magicinterp);
     if (toglCurrent.window == NULL)
diff --git a/graphics/grTk1.c b/graphics/grTk1.c
index d5d3e32f..d783d244 100644
--- a/graphics/grTk1.c
+++ b/graphics/grTk1.c
@@ -372,7 +372,7 @@ GrTkInit(dispType)
     int color_base, color_reserved;
     int status;
 
-    if (Tk_InitStubs(magicinterp, "8.5", 0) == NULL) return FALSE;
+    if (Tk_InitStubs(magicinterp, Tclmagic_InitStubsVersion, 0) == NULL) return FALSE;
 
     grCurrent.window = Tk_MainWindow(magicinterp);
 
diff --git a/lef/tcllef.c b/lef/tcllef.c
index c378b2a9..878d7af9 100644
--- a/lef/tcllef.c
+++ b/lef/tcllef.c
@@ -42,7 +42,7 @@ Magiclef_Init(interp)
     if (interp == NULL) return TCL_ERROR;
     if (Tcl_PkgRequire(interp, "Tclmagic", MAGIC_VERSION, 0) == NULL)
 	return TCL_ERROR;
-    if (Tcl_InitStubs(interp, "8.5", 0) == NULL) return TCL_ERROR;
+    if (Tcl_InitStubs(interp, Tclmagic_InitStubsVersion, 0) == NULL) return TCL_ERROR;
 
     TxPrintf("Auto-loading LEF/DEF module\n");
     TxFlushOut();
diff --git a/plot/tclplot.c b/plot/tclplot.c
index 348b7b9f..a590f4b5 100644
--- a/plot/tclplot.c
+++ b/plot/tclplot.c
@@ -46,7 +46,7 @@ Tclplot_Init(interp)
     if (interp == NULL) return TCL_ERROR;
     if (Tcl_PkgRequire(interp, "Tclmagic", MAGIC_VERSION, 0) == NULL)
 	return TCL_ERROR;
-    if (Tcl_InitStubs(interp, "8.5", 0) == NULL) return TCL_ERROR;
+    if (Tcl_InitStubs(interp, Tclmagic_InitStubsVersion, 0) == NULL) return TCL_ERROR;
 
     TxPrintf("Auto-loading PLOT module\n");
     TxFlushOut();
diff --git a/router/tclroute.c b/router/tclroute.c
index 0922b6f5..3426267b 100644
--- a/router/tclroute.c
+++ b/router/tclroute.c
@@ -53,7 +53,7 @@ Tclroute_Init(interp)
     if (interp == NULL) return TCL_ERROR;
     if (Tcl_PkgRequire(interp, "Tclmagic", MAGIC_VERSION, 0) == NULL)
 	return TCL_ERROR;
-    if (Tcl_InitStubs(interp, "8.5", 0) == NULL) return TCL_ERROR;
+    if (Tcl_InitStubs(interp, Tclmagic_InitStubsVersion, 0) == NULL) return TCL_ERROR;
 
     TxPrintf("Auto-loading ROUTE module\n");
     TxFlushOut();
diff --git a/tcltk/tclmagic.c b/tcltk/tclmagic.c
index 3314346a..48741630 100644
--- a/tcltk/tclmagic.c
+++ b/tcltk/tclmagic.c
@@ -53,6 +53,16 @@ char *MagicVersion = MAGIC_VERSION;
 char *MagicRevision = MAGIC_REVISION;
 char *MagicCompileTime = MAGIC_DATE;
 
+#if TCL_MAJOR_VERSION < 9
+const char *Tclmagic_InitStubsVersion = "8.5";
+#else
+/* Major version changed API (as you'd expect for a major version upgrade)
+ *  which is compiled into the resulting binary.
+ * No possibility of dual version support.
+ */
+const char *Tclmagic_InitStubsVersion = "9.0";
+#endif
+
 Tcl_Interp *magicinterp;
 Tcl_Interp *consoleinterp;
 
@@ -1293,7 +1303,7 @@ Tclmagic_Init(interp)
     /* Remember the interpreter */
     magicinterp = interp;
 
-    if (Tcl_InitStubs(interp, "8.5", 0) == NULL) return TCL_ERROR;
+    if (Tcl_InitStubs(interp, Tclmagic_InitStubsVersion, 0) == NULL) return TCL_ERROR;
 
     /* Initialization and Startup commands */
     Tcl_CreateCommand(interp, "magic::initialize", (Tcl_CmdProc *)_magic_initialize,
diff --git a/tcltk/tclmagic.h b/tcltk/tclmagic.h
index c9d411b2..c2dcbc61 100644
--- a/tcltk/tclmagic.h
+++ b/tcltk/tclmagic.h
@@ -28,5 +28,7 @@ extern int  TagVerify();
 extern int  Tcl_printf();
 extern void MakeWindowCommand();
 
+extern const char *Tclmagic_InitStubsVersion;
+
 #endif	/* MAGIC_WRAPPER */
 #endif /* _TCLMAGIC_H */