diff --git a/src/script/interpreter.h b/src/script/interpreter.h
--- a/src/script/interpreter.h
+++ b/src/script/interpreter.h
@@ -111,6 +111,10 @@
     // Do we accept activate replay protection using a different fork id.
     //
     SCRIPT_ENABLE_REPLAY_PROTECTION = (1U << 17),
+
+    // Enable new opcodes.
+    //
+    SCRIPT_ENABLE_MONOLITH_OPCODES = (1U << 18),
 };
 
 bool CheckSignatureEncoding(const std::vector<uint8_t> &vchSig, uint32_t flags,
diff --git a/src/test/data/script_tests.json b/src/test/data/script_tests.json
--- a/src/test/data/script_tests.json
+++ b/src/test/data/script_tests.json
@@ -818,25 +818,42 @@
 ["1", "2 3 2SWAP 1", "P2SH,STRICTENC", "INVALID_STACK_OPERATION"],
 
 ["'a' 'b'", "CAT", "P2SH,STRICTENC", "DISABLED_OPCODE", "CAT disabled"],
+["'a' 'b'", "CAT", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "CAT disabled"],
 ["'a' 'b' 0", "IF CAT ELSE 1 ENDIF", "P2SH,STRICTENC", "DISABLED_OPCODE", "CAT disabled"],
+["'a' 'b' 0", "IF CAT ELSE 1 ENDIF", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "CAT disabled"],
 ["'abc' 1 1", "SPLIT", "P2SH,STRICTENC", "DISABLED_OPCODE", "SPLIT disabled"],
+["'abc' 1 1", "SPLIT", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "SPLIT disabled"],
 ["'abc' 1 1 0", "IF SPLIT ELSE 1 ENDIF", "P2SH,STRICTENC", "DISABLED_OPCODE", "SPLIT disabled"],
+["'abc' 1 1 0", "IF SPLIT ELSE 1 ENDIF", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "SPLIT disabled"],
 ["'abc' 2 0", "IF NUM2BIN ELSE 1 ENDIF", "P2SH,STRICTENC", "DISABLED_OPCODE", "NUM2BIN disabled"],
+["'abc' 2 0", "IF NUM2BIN ELSE 1 ENDIF", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "NUM2BIN disabled"],
 ["'abc' 2 0", "IF BIN2NUM ELSE 1 ENDIF", "P2SH,STRICTENC", "DISABLED_OPCODE", "BIN2NUM disabled"],
+["'abc' 2 0", "IF BIN2NUM ELSE 1 ENDIF", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "BIN2NUM disabled"],
 
 ["NOP", "SIZE 1", "P2SH,STRICTENC", "INVALID_STACK_OPERATION"],
 
 ["'abc'", "IF INVERT ELSE 1 ENDIF", "P2SH,STRICTENC", "DISABLED_OPCODE", "INVERT disabled"],
+["'abc'", "IF INVERT ELSE 1 ENDIF", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "INVERT disabled"],
 ["1 2 0 IF AND ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC", "DISABLED_OPCODE", "AND disabled"],
+["1 2 0 IF AND ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "AND disabled"],
 ["1 2 0 IF OR ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC", "DISABLED_OPCODE", "OR disabled"],
+["1 2 0 IF OR ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "OR disabled"],
 ["1 2 0 IF XOR ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC", "DISABLED_OPCODE", "XOR disabled"],
+["1 2 0 IF XOR ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "XOR disabled"],
 ["2 0 IF 2MUL ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC", "DISABLED_OPCODE", "2MUL disabled"],
+["2 0 IF 2MUL ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "2MUL disabled"],
 ["2 0 IF 2DIV ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC", "DISABLED_OPCODE", "2DIV disabled"],
+["2 0 IF 2DIV ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "2DIV disabled"],
 ["2 2 0 IF MUL ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC", "DISABLED_OPCODE", "MUL disabled"],
+["2 2 0 IF MUL ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "MUL disabled"],
 ["2 2 0 IF DIV ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC", "DISABLED_OPCODE", "DIV disabled"],
+["2 2 0 IF DIV ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "DIV disabled"],
 ["2 2 0 IF MOD ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC", "DISABLED_OPCODE", "MOD disabled"],
+["2 2 0 IF MOD ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "MOD disabled"],
 ["2 2 0 IF LSHIFT ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC", "DISABLED_OPCODE", "LSHIFT disabled"],
+["2 2 0 IF LSHIFT ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "LSHIFT disabled"],
 ["2 2 0 IF RSHIFT ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC", "DISABLED_OPCODE", "RSHIFT disabled"],
+["2 2 0 IF RSHIFT ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "RSHIFT disabled"],
 
 ["", "EQUAL NOT", "P2SH,STRICTENC", "INVALID_STACK_OPERATION", "EQUAL must error when there are no stack items"],
 ["0", "EQUAL NOT", "P2SH,STRICTENC", "INVALID_STACK_OPERATION", "EQUAL must error when there are not 2 stack items"],
@@ -850,12 +867,19 @@
 ["'abcdef' NOT", "0 EQUAL", "P2SH,STRICTENC", "UNKNOWN_ERROR", "NOT is an arithmetic operand"],
 
 ["2 DUP MUL", "4 EQUAL", "P2SH,STRICTENC", "DISABLED_OPCODE", "disabled"],
+["2 DUP MUL", "4 EQUAL", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "disabled"],
 ["2 DUP DIV", "1 EQUAL", "P2SH,STRICTENC", "DISABLED_OPCODE", "disabled"],
+["2 DUP DIV", "1 EQUAL", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "disabled"],
 ["2 2MUL", "4 EQUAL", "P2SH,STRICTENC", "DISABLED_OPCODE", "disabled"],
+["2 2MUL", "4 EQUAL", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "disabled"],
 ["2 2DIV", "1 EQUAL", "P2SH,STRICTENC", "DISABLED_OPCODE", "disabled"],
+["2 2DIV", "1 EQUAL", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "disabled"],
 ["7 3 MOD", "1 EQUAL", "P2SH,STRICTENC", "DISABLED_OPCODE", "disabled"],
+["7 3 MOD", "1 EQUAL", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "disabled"],
 ["2 2 LSHIFT", "8 EQUAL", "P2SH,STRICTENC", "DISABLED_OPCODE", "disabled"],
+["2 2 LSHIFT", "8 EQUAL", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "disabled"],
 ["2 1 RSHIFT", "1 EQUAL", "P2SH,STRICTENC", "DISABLED_OPCODE", "disabled"],
+["2 1 RSHIFT", "1 EQUAL", "P2SH,STRICTENC,MONOLITH_OPCODES", "DISABLED_OPCODE", "disabled"],
 
 ["1", "NOP1 CHECKLOCKTIMEVERIFY CHECKSEQUENCEVERIFY NOP4 NOP5 NOP6 NOP7 NOP8 NOP9 NOP10 2 EQUAL", "P2SH,STRICTENC", "EVAL_FALSE"],
 ["'NOP_1_to_10' NOP1 CHECKLOCKTIMEVERIFY CHECKSEQUENCEVERIFY NOP4 NOP5 NOP6 NOP7 NOP8 NOP9 NOP10","'NOP_1_to_11' EQUAL", "P2SH,STRICTENC", "EVAL_FALSE"],
diff --git a/src/test/scriptflags.cpp b/src/test/scriptflags.cpp
--- a/src/test/scriptflags.cpp
+++ b/src/test/scriptflags.cpp
@@ -33,6 +33,7 @@
     {"COMPRESSED_PUBKEYTYPE", SCRIPT_VERIFY_COMPRESSED_PUBKEYTYPE},
     {"SIGHASH_FORKID", SCRIPT_ENABLE_SIGHASH_FORKID},
     {"REPLAY_PROTECTION", SCRIPT_ENABLE_REPLAY_PROTECTION},
+    {"MONOLITH_OPCODES", SCRIPT_ENABLE_MONOLITH_OPCODES},
 };
 
 uint32_t ParseScriptFlags(std::string strFlags) {