diff --git a/src/chainparams.h b/src/chainparams.h
--- a/src/chainparams.h
+++ b/src/chainparams.h
@@ -66,6 +66,8 @@
     bool DefaultConsistencyChecks() const { return fDefaultConsistencyChecks; }
     /** Policy: Filter transactions that do not match well-defined patterns */
     bool RequireStandard() const { return fRequireStandard; }
+    /** If this is a test chain */
+    bool IsTestChain() const { return m_is_test_chain; }
     uint64_t PruneAfterHeight() const { return nPruneAfterHeight; }
     /** Minimum free space (in GB) needed for data directory */
     uint64_t AssumedBlockchainSize() const { return m_assumed_blockchain_size; }
@@ -76,11 +78,8 @@
     uint64_t AssumedChainStateSize() const {
         return m_assumed_chain_state_size;
     }
-    /**
-     * Make miner stop after a block is found. In RPC, don't return until
-     * nGenProcLimit blocks are generated.
-     */
-    bool MineBlocksOnDemand() const { return fMineBlocksOnDemand; }
+    /** Whether it is possible to mine blocks on demand (no retargeting) */
+    bool MineBlocksOnDemand() const { return consensus.fPowNoRetargeting; }
     /** Return the BIP70 network string (main, test or regtest) */
     std::string NetworkIDString() const { return strNetworkID; }
     /** Return the list of hostnames to look up for DNS seeds */
@@ -111,7 +110,7 @@
     std::vector<SeedSpec6> vFixedSeeds;
     bool fDefaultConsistencyChecks;
     bool fRequireStandard;
-    bool fMineBlocksOnDemand;
+    bool m_is_test_chain;
     CCheckpointData checkpointData;
     ChainTxData chainTxData;
 };
diff --git a/src/chainparams.cpp b/src/chainparams.cpp
--- a/src/chainparams.cpp
+++ b/src/chainparams.cpp
@@ -235,7 +235,7 @@
 
         fDefaultConsistencyChecks = false;
         fRequireStandard = true;
-        fMineBlocksOnDemand = false;
+        m_is_test_chain = false;
 
         checkpointData = {
             .mapCheckpoints = {
@@ -452,7 +452,7 @@
 
         fDefaultConsistencyChecks = false;
         fRequireStandard = false;
-        fMineBlocksOnDemand = false;
+        m_is_test_chain = true;
 
         checkpointData = {
             .mapCheckpoints = {
@@ -612,8 +612,8 @@
         vSeeds.clear();
 
         fDefaultConsistencyChecks = true;
-        fRequireStandard = false;
-        fMineBlocksOnDemand = true;
+        fRequireStandard = true;
+        m_is_test_chain = true;
 
         checkpointData = {
             .mapCheckpoints = {
diff --git a/src/init.cpp b/src/init.cpp
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -1797,7 +1797,7 @@
 
     fRequireStandard =
         !gArgs.GetBoolArg("-acceptnonstdtxn", !chainparams.RequireStandard());
-    if (chainparams.RequireStandard() && !fRequireStandard) {
+    if (!chainparams.IsTestChain() && !fRequireStandard) {
         return InitError(
             strprintf("acceptnonstdtxn is not currently supported for %s chain",
                       chainparams.NetworkIDString()));
diff --git a/test/functional/abc-block-sigchecks-activation.py b/test/functional/abc-block-sigchecks-activation.py
--- a/test/functional/abc-block-sigchecks-activation.py
+++ b/test/functional/abc-block-sigchecks-activation.py
@@ -120,7 +120,8 @@
             "-replayprotectionactivationtime={}".format(
             REPLAY_PROTECTION_START_TIME),
             "-excessiveblocksize={}".format(MAXBLOCKSIZE),
-            "-blockmaxsize={}".format(MAXBLOCKSIZE)]]
+            "-blockmaxsize={}".format(MAXBLOCKSIZE),
+            "-acceptnonstdtxn=1"]]
 
     def getbestblock(self, node):
         """Get the best block. Register its height so we can use build_block."""
diff --git a/test/functional/abc-mempool-accept-txn.py b/test/functional/abc-mempool-accept-txn.py
--- a/test/functional/abc-mempool-accept-txn.py
+++ b/test/functional/abc-mempool-accept-txn.py
@@ -71,7 +71,8 @@
         self.tip = None
         self.blocks = {}
         self.extra_args = [
-            ['-phononactivationtime={}'.format(SIGOPS_DEACTIVATION_TIME)]]
+            ['-phononactivationtime={}'.format(SIGOPS_DEACTIVATION_TIME),
+             '-acceptnonstdtxn=1']]
 
     def add_options(self, parser):
         super().add_options(parser)
diff --git a/test/functional/abc-mempool-coherence-on-activations.py b/test/functional/abc-mempool-coherence-on-activations.py
--- a/test/functional/abc-mempool-coherence-on-activations.py
+++ b/test/functional/abc-mempool-coherence-on-activations.py
@@ -131,7 +131,8 @@
         self.tip = None
         self.blocks = {}
         self.extra_args = [['-whitelist=127.0.0.1',
-                            EXTRA_ARG]]
+                            EXTRA_ARG,
+                            '-acceptnonstdtxn=1']]
 
     def next_block(self, number):
         if self.tip is None:
diff --git a/test/functional/abc-minimaldata.py b/test/functional/abc-minimaldata.py
--- a/test/functional/abc-minimaldata.py
+++ b/test/functional/abc-minimaldata.py
@@ -51,6 +51,7 @@
     def set_test_params(self):
         self.num_nodes = 1
         self.block_heights = {}
+        self.extra_args = [['-acceptnonstdtxn=1']]
 
     def bootstrap_p2p(self, *, num_connections=1):
         """Add a P2P connection to the node.
diff --git a/test/functional/abc-op-reversebytes-activation.py b/test/functional/abc-op-reversebytes-activation.py
--- a/test/functional/abc-op-reversebytes-activation.py
+++ b/test/functional/abc-op-reversebytes-activation.py
@@ -53,7 +53,8 @@
         self.num_nodes = 1
         self.block_heights = {}
         self.extra_args = [
-            ["-phononactivationtime={}".format(PHONON_START_TIME)]]
+            ["-phononactivationtime={}".format(PHONON_START_TIME),
+             "-acceptnonstdtxn=1"]]
 
     def bootstrap_p2p(self, *, num_connections=1):
         """Add a P2P connection to the node.
diff --git a/test/functional/abc-phonon-mempoolpolicy.py b/test/functional/abc-phonon-mempoolpolicy.py
--- a/test/functional/abc-phonon-mempoolpolicy.py
+++ b/test/functional/abc-phonon-mempoolpolicy.py
@@ -53,7 +53,8 @@
         self.extra_args = [[
             "-phononactivationtime={}".format(PHONON_START_TIME),
             "-replayprotectionactivationtime={}".format(
-                REPLAY_PROTECTION_TIME)]]
+                REPLAY_PROTECTION_TIME),
+            "-acceptnonstdtxn=1"]]
 
     def bootstrap_p2p(self):
         self.nodes[0].add_p2p_connection(P2PDataStore())
diff --git a/test/functional/abc-replay-protection.py b/test/functional/abc-replay-protection.py
--- a/test/functional/abc-replay-protection.py
+++ b/test/functional/abc-replay-protection.py
@@ -61,7 +61,9 @@
         self.tip = None
         self.blocks = {}
         self.extra_args = [['-whitelist=127.0.0.1',
-                            "-replayprotectionactivationtime={}".format(REPLAY_PROTECTION_START_TIME)]]
+                            "-replayprotectionactivationtime={}".format(
+                                REPLAY_PROTECTION_START_TIME),
+                            "-acceptnonstdtxn=1"]]
 
     def next_block(self, number):
         if self.tip is None:
diff --git a/test/functional/abc-schnorr.py b/test/functional/abc-schnorr.py
--- a/test/functional/abc-schnorr.py
+++ b/test/functional/abc-schnorr.py
@@ -66,6 +66,8 @@
     def set_test_params(self):
         self.num_nodes = 1
         self.block_heights = {}
+        self.extra_args = [[
+            "-acceptnonstdtxn=1"]]
 
     def bootstrap_p2p(self, *, num_connections=1):
         """Add a P2P connection to the node.
diff --git a/test/functional/abc-schnorrmultisig.py b/test/functional/abc-schnorrmultisig.py
--- a/test/functional/abc-schnorrmultisig.py
+++ b/test/functional/abc-schnorrmultisig.py
@@ -70,6 +70,7 @@
     def set_test_params(self):
         self.num_nodes = 1
         self.block_heights = {}
+        self.extra_args = [["-acceptnonstdtxn=1"]]
 
     def bootstrap_p2p(self, *, num_connections=1):
         """Add a P2P connection to the node.
diff --git a/test/functional/abc-sigchecks-inputstandardness-activation.py b/test/functional/abc-sigchecks-inputstandardness-activation.py
--- a/test/functional/abc-sigchecks-inputstandardness-activation.py
+++ b/test/functional/abc-sigchecks-inputstandardness-activation.py
@@ -83,7 +83,8 @@
         self.extra_args = [["-phononactivationtime={}".format(
             SIGCHECKS_ACTIVATION_TIME),
             "-replayprotectionactivationtime={}".format(
-            REPLAY_PROTECTION_START_TIME), ]]
+            REPLAY_PROTECTION_START_TIME),
+            "-acceptnonstdtxn=1"]]
 
     def getbestblock(self, node):
         """Get the best block. Register its height so we can use build_block."""
diff --git a/test/functional/abc-sigops-deactivation.py b/test/functional/abc-sigops-deactivation.py
--- a/test/functional/abc-sigops-deactivation.py
+++ b/test/functional/abc-sigops-deactivation.py
@@ -133,7 +133,7 @@
             REPLAY_PROTECTION_START_TIME)]
         # many standardness rules are actually enforced on regtest, except for
         # P2SH sigops.
-        self.extra_args = [timeargs, timeargs + ['-acceptnonstdtxn=0']]
+        self.extra_args = [timeargs + ['-acceptnonstdtxn=1'], timeargs]
 
     def getbestblock(self, node):
         """Get the best block. Register its height so we can use build_block."""
diff --git a/test/functional/abc-sigops-mempool-mining.py b/test/functional/abc-sigops-mempool-mining.py
--- a/test/functional/abc-sigops-mempool-mining.py
+++ b/test/functional/abc-sigops-mempool-mining.py
@@ -112,7 +112,8 @@
         self.setup_clean_chain = True
         self.num_nodes = 1
         self.extra_args = [
-            ["-maxmempool=5", '-phononactivationtime={}'.format(SIGOPS_DEACTIVATION_TIME)]]
+            ["-maxmempool=5", '-phononactivationtime={}'.format(SIGOPS_DEACTIVATION_TIME),
+                "-acceptnonstdtxn=1"]]
         self.block_heights = {}
 
     def skip_test_if_missing_module(self):
diff --git a/test/functional/feature_bip68_sequence.py b/test/functional/feature_bip68_sequence.py
--- a/test/functional/feature_bip68_sequence.py
+++ b/test/functional/feature_bip68_sequence.py
@@ -46,7 +46,7 @@
 class BIP68Test(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 2
-        self.extra_args = [["-noparkdeepreorg", "-maxreorgdepth=-1"],
+        self.extra_args = [["-noparkdeepreorg", "-maxreorgdepth=-1", "-acceptnonstdtxn=1"],
                            ["-acceptnonstdtxn=0", "-maxreorgdepth=-1"]]
 
     def skip_test_if_missing_module(self):
diff --git a/test/functional/feature_block.py b/test/functional/feature_block.py
--- a/test/functional/feature_block.py
+++ b/test/functional/feature_block.py
@@ -70,7 +70,9 @@
     def set_test_params(self):
         self.num_nodes = 1
         self.setup_clean_chain = True
-        self.extra_args = [['-noparkdeepreorg', '-maxreorgdepth=-1']]
+        # This is a consensus block test, we don't care about tx policy
+        self.extra_args = [['-noparkdeepreorg',
+                            '-maxreorgdepth=-1', '-acceptnonstdtxn=1']]
 
     def run_test(self):
         node = self.nodes[0]  # convenience reference to the node
diff --git a/test/functional/feature_cltv.py b/test/functional/feature_cltv.py
--- a/test/functional/feature_cltv.py
+++ b/test/functional/feature_cltv.py
@@ -84,7 +84,11 @@
 class BIP65Test(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 1
-        self.extra_args = [['-whitelist=127.0.0.1']]
+        self.extra_args = [[
+            '-whitelist=127.0.0.1',
+            '-par=1',  # Use only one script thread to get the exact reject reason for testing
+            '-acceptnonstdtxn=1',  # cltv_invalidate is nonstandard
+        ]]
         self.setup_clean_chain = True
         self.rpc_timeout = 120
 
diff --git a/test/functional/feature_config_args.py b/test/functional/feature_config_args.py
--- a/test/functional/feature_config_args.py
+++ b/test/functional/feature_config_args.py
@@ -44,6 +44,12 @@
         self.nodes[0].assert_start_raises_init_error(
             expected_msg='Error: Config setting for -wallet only applied on regtest network when in [regtest] section.')
 
+        with open(inc_conf_file_path, 'w', encoding='utf-8') as conf:
+            conf.write('regtest=0\n')  # mainnet
+            conf.write('acceptnonstdtxn=1\n')
+        self.nodes[0].assert_start_raises_init_error(
+            expected_msg='Error: acceptnonstdtxn is not currently supported for main chain')
+
         with open(inc_conf_file_path, 'w', encoding='utf-8') as conf:
             conf.write('nono\n')
         self.nodes[0].assert_start_raises_init_error(
diff --git a/test/functional/feature_maxuploadtarget.py b/test/functional/feature_maxuploadtarget.py
--- a/test/functional/feature_maxuploadtarget.py
+++ b/test/functional/feature_maxuploadtarget.py
@@ -39,8 +39,7 @@
     def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
-        # Start a node with maxuploadtarget of 200 MB (/24h)
-        self.extra_args = [["-maxuploadtarget=200"]]
+        self.extra_args = [["-maxuploadtarget=200", "-acceptnonstdtxn=1"]]
 
         # Cache for utxos, as the listunspent may take a long time later in the
         # test
diff --git a/test/functional/mempool_limit.py b/test/functional/mempool_limit.py
--- a/test/functional/mempool_limit.py
+++ b/test/functional/mempool_limit.py
@@ -22,8 +22,11 @@
     def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
-
-        self.extra_args = [["-maxmempool=5", "-spendzeroconfchange=0"]]
+        self.extra_args = [[
+            "-acceptnonstdtxn=1",
+            "-maxmempool=5",
+            "-spendzeroconfchange=0",
+        ]]
 
     def skip_test_if_missing_module(self):
         self.skip_if_no_wallet()
diff --git a/test/functional/mining_prioritisetransaction.py b/test/functional/mining_prioritisetransaction.py
--- a/test/functional/mining_prioritisetransaction.py
+++ b/test/functional/mining_prioritisetransaction.py
@@ -21,7 +21,10 @@
     def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 2
-        self.extra_args = [["-printpriority=1"], ["-printpriority=1"]]
+        self.extra_args = [[
+            "-printpriority=1",
+            "-acceptnonstdtxn=1",
+        ]] * self.num_nodes
 
     def skip_test_if_missing_module(self):
         self.skip_if_no_wallet()
diff --git a/test/functional/p2p_compactblocks.py b/test/functional/p2p_compactblocks.py
--- a/test/functional/p2p_compactblocks.py
+++ b/test/functional/p2p_compactblocks.py
@@ -133,7 +133,8 @@
     def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 2
-        self.extra_args = [[], ["-txindex"]]
+        self.extra_args = [["-acceptnonstdtxn=1"],
+                           ["-txindex", "-acceptnonstdtxn=1"]]
         self.utxos = []
 
     def skip_test_if_missing_module(self):
diff --git a/test/functional/p2p_invalid_tx.py b/test/functional/p2p_invalid_tx.py
--- a/test/functional/p2p_invalid_tx.py
+++ b/test/functional/p2p_invalid_tx.py
@@ -32,6 +32,9 @@
 
     def set_test_params(self):
         self.num_nodes = 1
+        self.extra_args = [[
+            "-acceptnonstdtxn=1",
+        ]]
         self.setup_clean_chain = True
 
     def bootstrap_p2p(self, *, num_connections=1):
diff --git a/test/functional/wallet_basic.py b/test/functional/wallet_basic.py
--- a/test/functional/wallet_basic.py
+++ b/test/functional/wallet_basic.py
@@ -24,6 +24,9 @@
 class WalletTest(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 4
+        self.extra_args = [[
+            "-acceptnonstdtxn=1",
+        ]] * self.num_nodes
         self.setup_clean_chain = True
 
     def skip_test_if_missing_module(self):