diff --git a/cmpInt.h b/cmpInt.h
index 16ea905..ad1c6e1 100644
--- a/cmpInt.h
+++ b/cmpInt.h
@@ -62,6 +62,7 @@ Tcl_FetchInternalRep(Tcl_Obj *objPtr, const Tcl_ObjType *type) {
         (Tcl_ObjInternalRep *)(&objPtr->internalRep)
         : NULL;
 }
+
 static inline void
 Tcl_FreeInternalRep(Tcl_Obj *objPtr) {
     if (objPtr->typePtr != NULL) {
@@ -71,6 +72,19 @@ Tcl_FreeInternalRep(Tcl_Obj *objPtr) {
 	objPtr->typePtr = NULL;
     }
 }
+
+static inline void
+Tcl_StoreInternalRep(Tcl_Obj *objPtr, const Tcl_ObjType *typePtr,
+                        const Tcl_ObjInternalRep *irPtr) {
+    Tcl_FreeInternalRep(objPtr);
+    /* When irPtr == NULL, just leave objPtr with no internalrep for typePtr */
+    if (irPtr) {
+        objPtr->internalRep.twoPtrValue.ptr1 = irPtr->twoPtrValue.ptr1;
+        objPtr->internalRep.twoPtrValue.ptr2 = irPtr->twoPtrValue.ptr2;
+        objPtr->typePtr = typePtr;
+    }
+}
+
 #endif /* TCL_MAJOR_VERSION < 8 */
 
 /*
diff --git a/cmpRPkg.c b/cmpRPkg.c
index a349463..2b0c050 100644
--- a/cmpRPkg.c
+++ b/cmpRPkg.c
@@ -25,7 +25,7 @@ static char procCommand[] = CMP_PROC_COMMAND; /* "bcproc"  */
 typedef struct CmdTable
 {
     const char* cmdName;   /* unqualified, e.g. "bceval" */
-    Tcl_ObjCmdProc2* proc; /* implementation */
+    Tcl_ObjCmdProc* proc; /* implementation */
     int exportIt;          /* nonzero => export */
 } CmdTable;
 
@@ -62,7 +62,7 @@ static int RegisterCommand(Tcl_Interp* interp, const char* nsName, const CmdTabl
     Tcl_DStringAppend(&fq, "::", 2);
     Tcl_DStringAppend(&fq, cmd->cmdName, -1);
 
-    Tcl_CreateObjCommand2(interp, Tcl_DStringValue(&fq), cmd->proc, NULL, NULL);
+    Tcl_CreateObjCommand(interp, Tcl_DStringValue(&fq), cmd->proc, NULL, NULL);
     Tcl_DStringFree(&fq);
 
     if (cmd->exportIt)
@@ -89,12 +89,12 @@ int Tbcload_SafeInit(Tcl_Interp* interp)
 static int TbcloadInitInternal(Tcl_Interp* interp, int isSafe)
 {
 #ifdef USE_TCL_STUBS
-    if (!Tcl_InitStubs(interp, "9.0", 1))
+    if (!Tcl_InitStubs(interp, TCL_VERSION, 1))
     {
         return TCL_ERROR;
     }
 #else
-    if (Tcl_PkgRequire(interp, "Tcl", "9.0", 1) == NULL)
+    if (Tcl_PkgRequire(interp, "Tcl", TCL_VERSION, 1) == NULL)
     {
         return TCL_ERROR;
     }
diff --git a/cmpRead.c b/cmpRead.c
index 14fbc89..7ea3640 100644
--- a/cmpRead.c
+++ b/cmpRead.c
@@ -368,7 +368,7 @@ static void InitTypes();
  *----------------------------------------------------------------------
  */
 
-int Tbcload_EvalObjCmd(void* dummy, Tcl_Interp* interp, Tcl_Size objc, Tcl_Obj* const objv[])
+int Tbcload_EvalObjCmd(void* dummy, Tcl_Interp* interp, int objc, Tcl_Obj* const objv[])
 {
     ImageSignature sig;
     Tcl_Obj* cmdObjPtr;
@@ -434,7 +434,7 @@ int Tbcload_EvalObjCmd(void* dummy, Tcl_Interp* interp, Tcl_Size objc, Tcl_Obj*
  *----------------------------------------------------------------------
  */
 
-int Tbcload_ProcObjCmd(void* dummy, Tcl_Interp* interp, Tcl_Size objc, Tcl_Obj* const objv[])
+int Tbcload_ProcObjCmd(void* dummy, Tcl_Interp* interp, int objc, Tcl_Obj* const objv[])
 {
     return (*bcprocCmdProc)(dummy, interp, objc, objv);
 }
@@ -1933,10 +1933,10 @@ static Tcl_Obj* ExtractCompiledFile(Tcl_Interp* interp, char* codePtr, Tcl_Size
     InitExtractEnv(newCodePtr, (codePtr + codeLength), &exEnv);
 
     /*
-     * Do not allow loading newer bytecodes into older interps
+     * Do not allow loading bytecodes across major versions or into older versions.
      */
-    if ((exEnv.sig.tclMajorVersion > tclMajorVersion) ||
-        ((exEnv.sig.tclMajorVersion == tclMajorVersion) && (exEnv.sig.tclMinorVersion > tclMinorVersion)))
+    if ((exEnv.sig.tclMajorVersion != tclMajorVersion) ||
+        (exEnv.sig.tclMinorVersion > tclMinorVersion))
     {
         char buf[128];
 
@@ -2212,7 +2212,7 @@ static int InitCompatibilityLayer(Tcl_Interp* interp)
 
 int TbcloadInit(Tcl_Interp* interp)
 {
-    if (!Tcl_InitStubs(interp, "9.0", 1))
+    if (!Tcl_InitStubs(interp, TCL_VERSION, 1))
     {
         return TCL_ERROR;
     }
@@ -2299,8 +2299,8 @@ static int ExtractJumptableInfo(Tcl_Interp* interp, ExtractionEnv* envPtr, AuxDa
             goto errorReturn;
         }
         hEntry = Tcl_CreateHashEntry(&infoPtr->hashTable, key, &new);
-        Tcl_Free(key);
-        Tcl_SetHashValue(hEntry, (char*)value);
+        Tcl_Free((char *)key);
+        Tcl_SetHashValue(hEntry, (char*)(intptr_t)value);
     }
 
     /*
diff --git a/proTbcLoad.h b/proTbcLoad.h
index 7679561..588ea53 100644
--- a/proTbcLoad.h
+++ b/proTbcLoad.h
@@ -28,8 +28,8 @@
  *----------------------------------------------------------------
  */
 
-EXTERN int Tbcload_EvalObjCmd(void* dummy, Tcl_Interp* interp, Tcl_Size objc, Tcl_Obj* const objv[]);
-EXTERN int Tbcload_ProcObjCmd(void* dummy, Tcl_Interp* interp, Tcl_Size objc, Tcl_Obj* const objv[]);
+EXTERN Tcl_ObjCmdProc Tbcload_EvalObjCmd;
+EXTERN Tcl_ObjCmdProc Tbcload_ProcObjCmd;
 EXTERN const char* TbcloadGetPackageName(void);
 
 EXTERN int Tbcload_Init(Tcl_Interp* interp);