@@ -581,11 +581,46 @@ Tkapp_New(const char *screenName, const char *className,
     }
 
     v->OldBooleanType = Tcl_GetObjType("boolean");
-    v->BooleanType = Tcl_GetObjType("booleanString");
-    v->ByteArrayType = Tcl_GetObjType("bytearray");
-    v->DoubleType = Tcl_GetObjType("double");
     v->IntType = Tcl_GetObjType("int");
     v->WideIntType = Tcl_GetObjType("wideInt");
+    {
+        Tcl_Obj *value;
+        int boolValue;
+
+        /* Tcl 8.5 booleanString type is not registered
+           and is renamed to boolean in Tcl 9.0.
+           Based on approach suggested at
+           https://core.tcl-lang.org/tcl/info/3bb3bcf2da5b */
+        value = Tcl_NewStringObj("true", -1);
+        Tcl_GetBooleanFromObj(NULL, value, &boolValue);
+        //fprintf(stderr, "%s %p\n", value->typePtr->name, value->typePtr);
+        v->BooleanType = value->typePtr;
+        Tcl_DecrRefCount(value);
+
+        // As suggested by TIP 484
+        value = Tcl_NewIntObj(0);
+        //fprintf(stderr, "%s %p\n", value->typePtr->name, value->typePtr);
+        v->IntType = value->typePtr;
+        Tcl_DecrRefCount(value);
+
+        /* Retrieve the 64-bit type, which is either "wideInt" or "int";
+        the "wideInt" type is only available when the "int" type is 32-bit. */
+        value = Tcl_NewWideIntObj(
+            /* Must use a value wider than 32-bit here, otherwise
+               Tcl_NewWideIntObj() could return a 32-bit "int". */
+            (Tcl_WideInt)(1) << 32
+        );
+        //fprintf(stderr, "%s %p\n", value->typePtr->name, value->typePtr);
+        v->WideIntType = value->typePtr;
+        Tcl_DecrRefCount(value);
+
+        // bytearray type is not registered in Tcl 9.0
+        value = Tcl_NewByteArrayObj(NULL, 0);
+        //fprintf(stderr, "%s %p\n", value->typePtr->name, value->typePtr);
+        v->ByteArrayType = value->typePtr;
+        Tcl_DecrRefCount(value);
+    }
+    v->DoubleType = Tcl_GetObjType("double");
     v->BignumType = Tcl_GetObjType("bignum");
     v->ListType = Tcl_GetObjType("list");
     v->ProcBodyType = Tcl_GetObjType("procbody");
@@ -1092,10 +1127,12 @@ FromObj(TkappObject *tkapp, Tcl_Obj *value)
 
     if (value->typePtr == tkapp->BooleanType ||
         value->typePtr == tkapp->OldBooleanType) {
+        //fprintf(stderr, "fromBoolean\n");
         return fromBoolean(tkapp, value);
     }
 
     if (value->typePtr == tkapp->ByteArrayType) {
+        //fprintf(stderr, "got bytearray\n");
         int size;
         char *data = (char*)Tcl_GetByteArrayFromObj(value, &size);
         return PyBytes_FromStringAndSize(data, size);
@@ -1105,16 +1142,9 @@ FromObj(TkappObject *tkapp, Tcl_Obj *value)
         return PyFloat_FromDouble(value->internalRep.doubleValue);
     }
 
-    if (value->typePtr == tkapp->IntType) {
-        long longValue;
-        if (Tcl_GetLongFromObj(interp, value, &longValue) == TCL_OK)
-            return PyLong_FromLong(longValue);
-        /* If there is an error in the long conversion,
-           fall through to wideInt handling. */
-    }
-
     if (value->typePtr == tkapp->IntType ||
         value->typePtr == tkapp->WideIntType) {
+        //fprintf(stderr, "fromWideIntObj\n");
         result = fromWideIntObj(tkapp, value);
         if (result != NULL || PyErr_Occurred())
             return result;
@@ -1165,13 +1195,6 @@ FromObj(TkappObject *tkapp, Tcl_Obj *value)
         return unicodeFromTclObj(value);
     }
 
-    if (tkapp->BooleanType == NULL &&
-        strcmp(value->typePtr->name, "booleanString") == 0) {
-        /* booleanString type is not registered in Tcl */
-        tkapp->BooleanType = value->typePtr;
-        return fromBoolean(tkapp, value);
-    }
-
     if (tkapp->BignumType == NULL &&
         strcmp(value->typePtr->name, "bignum") == 0) {
         /* bignum type is not registered in Tcl */