diff --git a/cli-output/src/display.rs b/cli-output/src/display.rs
index 3d1c3e74fc..f1d52c1f67 100644
--- a/cli-output/src/display.rs
+++ b/cli-output/src/display.rs
@@ -140,7 +140,7 @@ fn format_account_mode(message: &Message, index: usize) -> String {
         } else {
             "-"
         },
-        if message.is_writable(index) {
+        if message.is_writable(index, /*demote_program_write_locks=*/ true) {
             "w" // comment for consistent rust fmt (no joking; lol)
         } else {
             "-"
diff --git a/core/src/banking_stage.rs b/core/src/banking_stage.rs
index 97bffd0931..16ea95fab6 100644
--- a/core/src/banking_stage.rs
+++ b/core/src/banking_stage.rs
@@ -1049,6 +1049,7 @@ impl BankingStage {
         libsecp256k1_fail_on_bad_count: bool,
         cost_tracker: &Arc<RwLock<CostTracker>>,
         banking_stage_stats: &BankingStageStats,
+        demote_program_write_locks: bool,
     ) -> (Vec<SanitizedTransaction>, Vec<usize>, Vec<usize>) {
         let mut retryable_transaction_packet_indexes: Vec<usize> = vec![];
 
@@ -1082,7 +1083,8 @@ impl BankingStage {
             verified_transactions_with_packet_indexes
                 .into_iter()
                 .filter_map(|(tx, tx_index)| {
-                    let result = cost_tracker_readonly.would_transaction_fit(&tx);
+                    let result = cost_tracker_readonly
+                        .would_transaction_fit(&tx, demote_program_write_locks);
                     if result.is_err() {
                         debug!("transaction {:?} would exceed limit: {:?}", tx, result);
                         retryable_transaction_packet_indexes.push(tx_index);
@@ -1165,6 +1167,7 @@ impl BankingStage {
                 bank.libsecp256k1_fail_on_bad_count(),
                 cost_tracker,
                 banking_stage_stats,
+                bank.demote_program_write_locks(),
             );
         packet_conversion_time.stop();
         inc_new_counter_info!("banking_stage-packet_conversion", 1);
@@ -1201,7 +1204,10 @@ impl BankingStage {
         let mut cost_tracking_time = Measure::start("cost_tracking_time");
         transactions.iter().enumerate().for_each(|(index, tx)| {
             if unprocessed_tx_indexes.iter().all(|&i| i != index) {
-                cost_tracker.write().unwrap().add_transaction_cost(tx);
+                cost_tracker
+                    .write()
+                    .unwrap()
+                    .add_transaction_cost(tx, bank.demote_program_write_locks());
             }
         });
         cost_tracking_time.stop();
@@ -1268,6 +1274,7 @@ impl BankingStage {
                 bank.libsecp256k1_fail_on_bad_count(),
                 cost_tracker,
                 banking_stage_stats,
+                bank.demote_program_write_locks(),
             );
         unprocessed_packet_conversion_time.stop();
 
diff --git a/core/src/cost_model.rs b/core/src/cost_model.rs
index fcaf6d719e..ade82ea8e7 100644
--- a/core/src/cost_model.rs
+++ b/core/src/cost_model.rs
@@ -113,7 +113,11 @@ impl CostModel {
         );
     }
 
-    pub fn calculate_cost(&mut self, transaction: &SanitizedTransaction) -> &TransactionCost {
+    pub fn calculate_cost(
+        &mut self,
+        transaction: &SanitizedTransaction,
+        demote_program_write_locks: bool,
+    ) -> &TransactionCost {
         self.transaction_cost.reset();
 
         // calculate transaction exeution cost
@@ -122,7 +126,7 @@ impl CostModel {
         // calculate account access cost
         let message = transaction.message();
         message.account_keys_iter().enumerate().for_each(|(i, k)| {
-            let is_writable = message.is_writable(i);
+            let is_writable = message.is_writable(i, demote_program_write_locks);
 
             if is_writable {
                 self.transaction_cost.writable_accounts.push(*k);
@@ -353,7 +357,7 @@ mod tests {
         .unwrap();
 
         let mut cost_model = CostModel::default();
-        let tx_cost = cost_model.calculate_cost(&tx);
+        let tx_cost = cost_model.calculate_cost(&tx, /*demote_program_write_locks=*/ true);
         assert_eq!(2 + 2, tx_cost.writable_accounts.len());
         assert_eq!(signer1.pubkey(), tx_cost.writable_accounts[0]);
         assert_eq!(signer2.pubkey(), tx_cost.writable_accounts[1]);
@@ -395,7 +399,7 @@ mod tests {
         cost_model
             .upsert_instruction_cost(&system_program::id(), expected_execution_cost)
             .unwrap();
-        let tx_cost = cost_model.calculate_cost(&tx);
+        let tx_cost = cost_model.calculate_cost(&tx, /*demote_program_write_locks=*/ true);
         assert_eq!(expected_account_cost, tx_cost.account_access_cost);
         assert_eq!(expected_execution_cost, tx_cost.execution_cost);
         assert_eq!(2, tx_cost.writable_accounts.len());
@@ -465,7 +469,8 @@ mod tests {
                 } else {
                     thread::spawn(move || {
                         let mut cost_model = cost_model.write().unwrap();
-                        let tx_cost = cost_model.calculate_cost(&tx);
+                        let tx_cost = cost_model
+                            .calculate_cost(&tx, /*demote_program_write_locks=*/ true);
                         assert_eq!(3, tx_cost.writable_accounts.len());
                         assert_eq!(expected_account_cost, tx_cost.account_access_cost);
                     })
diff --git a/core/src/cost_tracker.rs b/core/src/cost_tracker.rs
index 0d9f32b280..40a86133ad 100644
--- a/core/src/cost_tracker.rs
+++ b/core/src/cost_tracker.rs
@@ -46,18 +46,23 @@ impl CostTracker {
     pub fn would_transaction_fit(
         &self,
         transaction: &SanitizedTransaction,
+        demote_program_write_locks: bool,
     ) -> Result<(), CostModelError> {
         let mut cost_model = self.cost_model.write().unwrap();
-        let tx_cost = cost_model.calculate_cost(transaction);
+        let tx_cost = cost_model.calculate_cost(transaction, demote_program_write_locks);
         self.would_fit(
             &tx_cost.writable_accounts,
             &(tx_cost.account_access_cost + tx_cost.execution_cost),
         )
     }
 
-    pub fn add_transaction_cost(&mut self, transaction: &SanitizedTransaction) {
+    pub fn add_transaction_cost(
+        &mut self,
+        transaction: &SanitizedTransaction,
+        demote_program_write_locks: bool,
+    ) {
         let mut cost_model = self.cost_model.write().unwrap();
-        let tx_cost = cost_model.calculate_cost(transaction);
+        let tx_cost = cost_model.calculate_cost(transaction, demote_program_write_locks);
         let cost = tx_cost.account_access_cost + tx_cost.execution_cost;
         for account_key in tx_cost.writable_accounts.iter() {
             *self
diff --git a/ledger-tool/src/main.rs b/ledger-tool/src/main.rs
index 67e27375e7..a5ed2ac8e3 100644
--- a/ledger-tool/src/main.rs
+++ b/ledger-tool/src/main.rs
@@ -792,7 +792,10 @@ fn compute_slot_cost(blockstore: &Blockstore, slot: Slot) -> Result<(), String>
             .for_each(|transaction| {
                 num_programs += transaction.message().instructions().len();
 
-                let tx_cost = cost_model.calculate_cost(&transaction);
+                let tx_cost = cost_model.calculate_cost(
+                    &transaction,
+                    true, // demote_program_write_locks
+                );
                 if cost_tracker.try_add(tx_cost).is_err() {
                     println!(
                         "Slot: {}, CostModel rejected transaction {:?}, stats {:?}!",
diff --git a/program-runtime/src/instruction_processor.rs b/program-runtime/src/instruction_processor.rs
index 7b5ed32b57..49c6381be1 100644
--- a/program-runtime/src/instruction_processor.rs
+++ b/program-runtime/src/instruction_processor.rs
@@ -4,6 +4,7 @@ use solana_sdk::{
     account::{AccountSharedData, ReadableAccount, WritableAccount},
     account_utils::StateMut,
     bpf_loader_upgradeable::{self, UpgradeableLoaderState},
+    feature_set::demote_program_write_locks,
     ic_logger_msg, ic_msg,
     instruction::{CompiledInstruction, Instruction, InstructionError},
     keyed_account::{keyed_account_at_index, KeyedAccount},
@@ -347,6 +348,7 @@ impl InstructionProcessor {
         instruction: &'a CompiledInstruction,
         executable_accounts: &'a [(Pubkey, Rc<RefCell<AccountSharedData>>)],
         accounts: &'a [(Pubkey, Rc<RefCell<AccountSharedData>>)],
+        demote_program_write_locks: bool,
     ) -> Vec<(bool, bool, &'a Pubkey, &'a RefCell<AccountSharedData>)> {
         executable_accounts
             .iter()
@@ -355,7 +357,7 @@ impl InstructionProcessor {
                 let index = *index as usize;
                 (
                     message.is_signer(index),
-                    message.is_writable(index),
+                    message.is_writable(index, demote_program_write_locks),
                     &accounts[index].0,
                     &accounts[index].1 as &RefCell<AccountSharedData>,
                 )
@@ -600,6 +602,8 @@ impl InstructionProcessor {
 
         {
             let invoke_context = invoke_context.borrow();
+            let demote_program_write_locks =
+                invoke_context.is_feature_active(&demote_program_write_locks::id());
             let keyed_accounts = invoke_context.get_keyed_accounts()?;
             for (src_keyed_account_index, ((_key, account), dst_keyed_account_index)) in accounts
                 .iter()
@@ -608,7 +612,9 @@ impl InstructionProcessor {
             {
                 let dst_keyed_account = &keyed_accounts[dst_keyed_account_index];
                 let src_keyed_account = account.borrow();
-                if message.is_writable(src_keyed_account_index) && !src_keyed_account.executable() {
+                if message.is_writable(src_keyed_account_index, demote_program_write_locks)
+                    && !src_keyed_account.executable()
+                {
                     if dst_keyed_account.data_len()? != src_keyed_account.data().len()
                         && dst_keyed_account.data_len()? != 0
                     {
@@ -652,8 +658,15 @@ impl InstructionProcessor {
             invoke_context.verify_and_update(instruction, accounts, caller_write_privileges)?;
 
             // Construct keyed accounts
-            let keyed_accounts =
-                Self::create_keyed_accounts(message, instruction, executable_accounts, accounts);
+            let demote_program_write_locks =
+                invoke_context.is_feature_active(&demote_program_write_locks::id());
+            let keyed_accounts = Self::create_keyed_accounts(
+                message,
+                instruction,
+                executable_accounts,
+                accounts,
+                demote_program_write_locks,
+            );
 
             // Invoke callee
             invoke_context.push(program_id, &keyed_accounts)?;
@@ -671,7 +684,7 @@ impl InstructionProcessor {
             if result.is_ok() {
                 // Verify the called program has not misbehaved
                 let write_privileges: Vec<bool> = (0..message.account_keys.len())
-                    .map(|i| message.is_writable(i))
+                    .map(|i| message.is_writable(i, demote_program_write_locks))
                     .collect();
                 result = invoke_context.verify_and_update(instruction, accounts, &write_privileges);
             }
diff --git a/program-test/src/lib.rs b/program-test/src/lib.rs
index 0db2d01c19..da1ef80d86 100644
--- a/program-test/src/lib.rs
+++ b/program-test/src/lib.rs
@@ -24,6 +24,7 @@ use {
         compute_budget::ComputeBudget,
         entrypoint::{ProgramResult, SUCCESS},
         epoch_schedule::EpochSchedule,
+        feature_set::demote_program_write_locks,
         fee_calculator::{FeeCalculator, FeeRateGovernor},
         genesis_config::{ClusterType, GenesisConfig},
         hash::Hash,
@@ -261,12 +262,14 @@ impl solana_sdk::program_stubs::SyscallStubs for SyscallStubs {
             }
             panic!("Program id {} wasn't found in account_infos", program_id);
         };
+        let demote_program_write_locks =
+            invoke_context.is_feature_active(&demote_program_write_locks::id());
         // TODO don't have the caller's keyed_accounts so can't validate writer or signer escalation or deescalation yet
         let caller_privileges = message
             .account_keys
             .iter()
             .enumerate()
-            .map(|(i, _)| message.is_writable(i))
+            .map(|(i, _)| message.is_writable(i, demote_program_write_locks))
             .collect::<Vec<bool>>();
 
         stable_log::program_invoke(&logger, &program_id, invoke_context.invoke_depth());
@@ -337,7 +340,7 @@ impl solana_sdk::program_stubs::SyscallStubs for SyscallStubs {
 
         // Copy writeable account modifications back into the caller's AccountInfos
         for (i, (pubkey, account)) in accounts.iter().enumerate().take(message.account_keys.len()) {
-            if !message.is_writable(i) {
+            if !message.is_writable(i, demote_program_write_locks) {
                 continue;
             }
             for account_info in account_infos {
diff --git a/programs/bpf/tests/programs.rs b/programs/bpf/tests/programs.rs
index 11ce9581d4..cc337f4868 100644
--- a/programs/bpf/tests/programs.rs
+++ b/programs/bpf/tests/programs.rs
@@ -1796,7 +1796,7 @@ fn test_program_bpf_upgrade_and_invoke_in_same_tx() {
         "solana_bpf_rust_panic",
     );
 
-    // Invoke, then upgrade the program, and then invoke again in same tx
+    // Attempt to invoke, then upgrade the program in same tx
     let message = Message::new(
         &[
             invoke_instruction.clone(),
@@ -1815,10 +1815,12 @@ fn test_program_bpf_upgrade_and_invoke_in_same_tx() {
         message.clone(),
         bank.last_blockhash(),
     );
+    // program_id is automatically demoted to readonly, preventing the upgrade, which requires
+    // writeability
     let (result, _) = process_transaction_and_record_inner(&bank, tx);
     assert_eq!(
         result.unwrap_err(),
-        TransactionError::InstructionError(2, InstructionError::ProgramFailedToComplete)
+        TransactionError::InstructionError(1, InstructionError::InvalidArgument)
     );
 }
 
@@ -2114,96 +2116,6 @@ fn test_program_bpf_upgrade_via_cpi() {
     assert_ne!(programdata, original_programdata);
 }
 
-#[cfg(feature = "bpf_rust")]
-#[test]
-fn test_program_bpf_upgrade_self_via_cpi() {
-    solana_logger::setup();
-
-    let GenesisConfigInfo {
-        genesis_config,
-        mint_keypair,
-        ..
-    } = create_genesis_config(50);
-    let mut bank = Bank::new_for_tests(&genesis_config);
-    let (name, id, entrypoint) = solana_bpf_loader_program!();
-    bank.add_builtin(&name, id, entrypoint);
-    let (name, id, entrypoint) = solana_bpf_loader_upgradeable_program!();
-    bank.add_builtin(&name, id, entrypoint);
-    let bank = Arc::new(bank);
-    let bank_client = BankClient::new_shared(&bank);
-    let noop_program_id = load_bpf_program(
-        &bank_client,
-        &bpf_loader::id(),
-        &mint_keypair,
-        "solana_bpf_rust_noop",
-    );
-
-    // Deploy upgradeable program
-    let buffer_keypair = Keypair::new();
-    let program_keypair = Keypair::new();
-    let program_id = program_keypair.pubkey();
-    let authority_keypair = Keypair::new();
-    load_upgradeable_bpf_program(
-        &bank_client,
-        &mint_keypair,
-        &buffer_keypair,
-        &program_keypair,
-        &authority_keypair,
-        "solana_bpf_rust_invoke_and_return",
-    );
-
-    let mut invoke_instruction = Instruction::new_with_bytes(
-        program_id,
-        &[0],
-        vec![
-            AccountMeta::new(noop_program_id, false),
-            AccountMeta::new(noop_program_id, false),
-            AccountMeta::new(clock::id(), false),
-        ],
-    );
-
-    // Call the upgraded program
-    invoke_instruction.data[0] += 1;
-    let result =
-        bank_client.send_and_confirm_instruction(&mint_keypair, invoke_instruction.clone());
-    assert!(result.is_ok());
-
-    // Prepare for upgrade
-    let buffer_keypair = Keypair::new();
-    load_upgradeable_buffer(
-        &bank_client,
-        &mint_keypair,
-        &buffer_keypair,
-        &authority_keypair,
-        "solana_bpf_rust_panic",
-    );
-
-    // Invoke, then upgrade the program, and then invoke again in same tx
-    let message = Message::new(
-        &[
-            invoke_instruction.clone(),
-            bpf_loader_upgradeable::upgrade(
-                &program_id,
-                &buffer_keypair.pubkey(),
-                &authority_keypair.pubkey(),
-                &mint_keypair.pubkey(),
-            ),
-            invoke_instruction,
-        ],
-        Some(&mint_keypair.pubkey()),
-    );
-    let tx = Transaction::new(
-        &[&mint_keypair, &authority_keypair],
-        message.clone(),
-        bank.last_blockhash(),
-    );
-    let (result, _) = process_transaction_and_record_inner(&bank, tx);
-    assert_eq!(
-        result.unwrap_err(),
-        TransactionError::InstructionError(2, InstructionError::ProgramFailedToComplete)
-    );
-}
-
 #[cfg(feature = "bpf_rust")]
 #[test]
 fn test_program_bpf_set_upgrade_authority_via_cpi() {
diff --git a/programs/bpf_loader/src/syscalls.rs b/programs/bpf_loader/src/syscalls.rs
index 847fe820ca..ba1c1aeda7 100644
--- a/programs/bpf_loader/src/syscalls.rs
+++ b/programs/bpf_loader/src/syscalls.rs
@@ -21,9 +21,9 @@ use solana_sdk::{
     entrypoint::{MAX_PERMITTED_DATA_INCREASE, SUCCESS},
     epoch_schedule::EpochSchedule,
     feature_set::{
-        blake3_syscall_enabled, close_upgradeable_program_accounts, disable_fees_sysvar,
-        enforce_aligned_host_addrs, libsecp256k1_0_5_upgrade_enabled, mem_overlap_fix,
-        secp256k1_recover_syscall_enabled,
+        blake3_syscall_enabled, close_upgradeable_program_accounts, demote_program_write_locks,
+        disable_fees_sysvar, enforce_aligned_host_addrs, libsecp256k1_0_5_upgrade_enabled,
+        mem_overlap_fix, secp256k1_recover_syscall_enabled,
     },
     hash::{Hasher, HASH_BYTES},
     ic_msg,
@@ -2293,7 +2293,14 @@ fn call<'a>(
     signers_seeds_len: u64,
     memory_mapping: &MemoryMapping,
 ) -> Result<u64, EbpfError<BpfError>> {
-    let (message, executables, accounts, account_refs, caller_write_privileges) = {
+    let (
+        message,
+        executables,
+        accounts,
+        account_refs,
+        caller_write_privileges,
+        demote_program_write_locks,
+    ) = {
         let invoke_context = syscall.get_context()?;
 
         invoke_context
@@ -2388,6 +2395,7 @@ fn call<'a>(
             accounts,
             account_refs,
             caller_write_privileges,
+            invoke_context.is_feature_active(&demote_program_write_locks::id()),
         )
     };
 
@@ -2413,7 +2421,7 @@ fn call<'a>(
         for (i, ((_key, account), account_ref)) in accounts.iter().zip(account_refs).enumerate() {
             let account = account.borrow();
             if let Some(mut account_ref) = account_ref {
-                if message.is_writable(i) && !account.executable() {
+                if message.is_writable(i, demote_program_write_locks) && !account.executable() {
                     *account_ref.lamports = account.lamports();
                     *account_ref.owner = *account.owner();
                     if account_ref.data.len() != account.data().len() {
diff --git a/rpc/src/transaction_status_service.rs b/rpc/src/transaction_status_service.rs
index 43a76dc51c..62630d3a17 100644
--- a/rpc/src/transaction_status_service.rs
+++ b/rpc/src/transaction_status_service.rs
@@ -113,7 +113,8 @@ impl TransactionStatusService {
                             })
                             .expect("FeeCalculator must exist");
                         let fee = transaction.message().calculate_fee(&fee_calculator);
-                        let tx_account_locks = transaction.get_account_locks();
+                        let tx_account_locks =
+                            transaction.get_account_locks(bank.demote_program_write_locks());
 
                         let inner_instructions = inner_instructions.map(|inner_instructions| {
                             inner_instructions
diff --git a/runtime/src/accounts.rs b/runtime/src/accounts.rs
index 015640a3ac..5fade1b981 100644
--- a/runtime/src/accounts.rs
+++ b/runtime/src/accounts.rs
@@ -201,8 +201,9 @@ impl Accounts {
     fn construct_instructions_account(
         message: &SanitizedMessage,
         is_owned_by_sysvar: bool,
+        demote_program_write_locks: bool,
     ) -> AccountSharedData {
-        let mut data = message.serialize_instructions();
+        let mut data = message.serialize_instructions(demote_program_write_locks);
         // add room for current instruction index.
         data.resize(data.len() + 2, 0);
         let owner = if is_owned_by_sysvar {
@@ -240,6 +241,8 @@ impl Accounts {
             let mut account_deps = Vec::with_capacity(message.account_keys_len());
             let mut rent_debits = RentDebits::default();
             let rent_for_sysvars = feature_set.is_active(&feature_set::rent_for_sysvars::id());
+            let demote_program_write_locks =
+                feature_set.is_active(&feature_set::demote_program_write_locks::id());
 
             for (i, key) in message.account_keys_iter().enumerate() {
                 let account = if message.is_non_loader_key(i) {
@@ -248,20 +251,21 @@ impl Accounts {
                     }
 
                     if solana_sdk::sysvar::instructions::check_id(key) {
-                        if message.is_writable(i) {
+                        if message.is_writable(i, demote_program_write_locks) {
                             return Err(TransactionError::InvalidAccountIndex);
                         }
                         Self::construct_instructions_account(
                             message,
                             feature_set
                                 .is_active(&feature_set::instructions_sysvar_owned_by_sysvar::id()),
+                            demote_program_write_locks,
                         )
                     } else {
                         let (account, rent) = self
                             .accounts_db
                             .load_with_fixed_root(ancestors, key)
                             .map(|(mut account, _)| {
-                                if message.is_writable(i) {
+                                if message.is_writable(i, demote_program_write_locks) {
                                     let rent_due = rent_collector.collect_from_existing_account(
                                         key,
                                         &mut account,
@@ -886,8 +890,11 @@ impl Accounts {
     pub fn lock_accounts<'a>(
         &self,
         txs: impl Iterator<Item = &'a SanitizedTransaction>,
+        demote_program_write_locks: bool,
     ) -> Vec<Result<()>> {
-        let keys: Vec<_> = txs.map(|tx| tx.get_account_locks()).collect();
+        let keys: Vec<_> = txs
+            .map(|tx| tx.get_account_locks(demote_program_write_locks))
+            .collect();
         let mut account_locks = &mut self.account_locks.lock().unwrap();
         keys.into_iter()
             .map(|keys| self.lock_account(&mut account_locks, keys.writable, keys.readonly))
@@ -900,6 +907,7 @@ impl Accounts {
         &self,
         txs: impl Iterator<Item = &'a SanitizedTransaction>,
         results: &[Result<()>],
+        demote_program_write_locks: bool,
     ) {
         let keys: Vec<_> = txs
             .zip(results)
@@ -907,7 +915,7 @@ impl Accounts {
                 Err(TransactionError::AccountInUse) => None,
                 Err(TransactionError::SanitizeFailure) => None,
                 Err(TransactionError::AccountLoadedTwice) => None,
-                _ => Some(tx.get_account_locks()),
+                _ => Some(tx.get_account_locks(demote_program_write_locks)),
             })
             .collect();
         let mut account_locks = self.account_locks.lock().unwrap();
@@ -930,6 +938,7 @@ impl Accounts {
         last_blockhash_with_fee_calculator: &(Hash, FeeCalculator),
         rent_for_sysvars: bool,
         merge_nonce_error_into_system_error: bool,
+        demote_program_write_locks: bool,
     ) {
         let accounts_to_store = self.collect_accounts_to_store(
             txs,
@@ -939,6 +948,7 @@ impl Accounts {
             last_blockhash_with_fee_calculator,
             rent_for_sysvars,
             merge_nonce_error_into_system_error,
+            demote_program_write_locks,
         );
         self.accounts_db.store_cached(slot, &accounts_to_store);
     }
@@ -964,6 +974,7 @@ impl Accounts {
         last_blockhash_with_fee_calculator: &(Hash, FeeCalculator),
         rent_for_sysvars: bool,
         merge_nonce_error_into_system_error: bool,
+        demote_program_write_locks: bool,
     ) -> Vec<(&'a Pubkey, &'a AccountSharedData)> {
         let mut accounts = Vec::with_capacity(loaded.len());
         for (i, ((raccs, _nonce_rollback), tx)) in loaded.iter_mut().zip(txs).enumerate() {
@@ -1012,7 +1023,7 @@ impl Accounts {
                     fee_payer_index = Some(i);
                 }
                 let is_fee_payer = Some(i) == fee_payer_index;
-                if message.is_writable(i)
+                if message.is_writable(i, demote_program_write_locks)
                     && (res.is_ok()
                         || (maybe_nonce_rollback.is_some() && (is_nonce_account || is_fee_payer)))
                 {
@@ -1731,6 +1742,8 @@ mod tests {
         accounts.store_slow_uncached(0, &keypair2.pubkey(), &account2);
         accounts.store_slow_uncached(0, &keypair3.pubkey(), &account3);
 
+        let demote_program_write_locks = true;
+
         let instructions = vec![CompiledInstruction::new(2, &(), vec![0, 1])];
         let message = Message::new_with_compiled_instructions(
             1,
@@ -1741,7 +1754,7 @@ mod tests {
             instructions,
         );
         let tx = new_sanitized_tx(&[&keypair0], message, Hash::default());
-        let results0 = accounts.lock_accounts([tx.clone()].iter());
+        let results0 = accounts.lock_accounts([tx.clone()].iter(), demote_program_write_locks);
 
         assert!(results0[0].is_ok());
         assert_eq!(
@@ -1776,7 +1789,7 @@ mod tests {
         );
         let tx1 = new_sanitized_tx(&[&keypair1], message, Hash::default());
         let txs = vec![tx0, tx1];
-        let results1 = accounts.lock_accounts(txs.iter());
+        let results1 = accounts.lock_accounts(txs.iter(), demote_program_write_locks);
 
         assert!(results1[0].is_ok()); // Read-only account (keypair1) can be referenced multiple times
         assert!(results1[1].is_err()); // Read-only account (keypair1) cannot also be locked as writable
@@ -1791,8 +1804,8 @@ mod tests {
             2
         );
 
-        accounts.unlock_accounts([tx].iter(), &results0);
-        accounts.unlock_accounts(txs.iter(), &results1);
+        accounts.unlock_accounts([tx].iter(), &results0, demote_program_write_locks);
+        accounts.unlock_accounts(txs.iter(), &results1, demote_program_write_locks);
         let instructions = vec![CompiledInstruction::new(2, &(), vec![0, 1])];
         let message = Message::new_with_compiled_instructions(
             1,
@@ -1803,7 +1816,7 @@ mod tests {
             instructions,
         );
         let tx = new_sanitized_tx(&[&keypair1], message, Hash::default());
-        let results2 = accounts.lock_accounts([tx].iter());
+        let results2 = accounts.lock_accounts([tx].iter(), demote_program_write_locks);
         assert!(results2[0].is_ok()); // Now keypair1 account can be locked as writable
 
         // Check that read-only lock with zero references is deleted
@@ -1840,6 +1853,8 @@ mod tests {
         accounts.store_slow_uncached(0, &keypair1.pubkey(), &account1);
         accounts.store_slow_uncached(0, &keypair2.pubkey(), &account2);
 
+        let demote_program_write_locks = true;
+
         let accounts_arc = Arc::new(accounts);
 
         let instructions = vec![CompiledInstruction::new(2, &(), vec![0, 1])];
@@ -1872,13 +1887,15 @@ mod tests {
             let exit_clone = exit_clone.clone();
             loop {
                 let txs = vec![writable_tx.clone()];
-                let results = accounts_clone.clone().lock_accounts(txs.iter());
+                let results = accounts_clone
+                    .clone()
+                    .lock_accounts(txs.iter(), demote_program_write_locks);
                 for result in results.iter() {
                     if result.is_ok() {
                         counter_clone.clone().fetch_add(1, Ordering::SeqCst);
                     }
                 }
-                accounts_clone.unlock_accounts(txs.iter(), &results);
+                accounts_clone.unlock_accounts(txs.iter(), &results, demote_program_write_locks);
                 if exit_clone.clone().load(Ordering::Relaxed) {
                     break;
                 }
@@ -1887,18 +1904,85 @@ mod tests {
         let counter_clone = counter;
         for _ in 0..5 {
             let txs = vec![readonly_tx.clone()];
-            let results = accounts_arc.clone().lock_accounts(txs.iter());
+            let results = accounts_arc
+                .clone()
+                .lock_accounts(txs.iter(), demote_program_write_locks);
             if results[0].is_ok() {
                 let counter_value = counter_clone.clone().load(Ordering::SeqCst);
                 thread::sleep(time::Duration::from_millis(50));
                 assert_eq!(counter_value, counter_clone.clone().load(Ordering::SeqCst));
             }
-            accounts_arc.unlock_accounts(txs.iter(), &results);
+            accounts_arc.unlock_accounts(txs.iter(), &results, demote_program_write_locks);
             thread::sleep(time::Duration::from_millis(50));
         }
         exit.store(true, Ordering::Relaxed);
     }
 
+    #[test]
+    fn test_demote_program_write_locks() {
+        let keypair0 = Keypair::new();
+        let keypair1 = Keypair::new();
+        let keypair2 = Keypair::new();
+        let keypair3 = Keypair::new();
+
+        let account0 = AccountSharedData::new(1, 0, &Pubkey::default());
+        let account1 = AccountSharedData::new(2, 0, &Pubkey::default());
+        let account2 = AccountSharedData::new(3, 0, &Pubkey::default());
+        let account3 = AccountSharedData::new(4, 0, &Pubkey::default());
+
+        let accounts = Accounts::new_with_config_for_tests(
+            Vec::new(),
+            &ClusterType::Development,
+            AccountSecondaryIndexes::default(),
+            false,
+            AccountShrinkThreshold::default(),
+        );
+        accounts.store_slow_uncached(0, &keypair0.pubkey(), &account0);
+        accounts.store_slow_uncached(0, &keypair1.pubkey(), &account1);
+        accounts.store_slow_uncached(0, &keypair2.pubkey(), &account2);
+        accounts.store_slow_uncached(0, &keypair3.pubkey(), &account3);
+
+        let demote_program_write_locks = true;
+
+        let instructions = vec![CompiledInstruction::new(2, &(), vec![0, 1])];
+        let message = Message::new_with_compiled_instructions(
+            1,
+            0,
+            0, // All accounts marked as writable
+            vec![keypair0.pubkey(), keypair1.pubkey(), native_loader::id()],
+            Hash::default(),
+            instructions,
+        );
+        let tx = new_sanitized_tx(&[&keypair0], message, Hash::default());
+        let results0 = accounts.lock_accounts([tx].iter(), demote_program_write_locks);
+
+        assert!(results0[0].is_ok());
+        // Instruction program-id account demoted to readonly
+        assert_eq!(
+            *accounts
+                .account_locks
+                .lock()
+                .unwrap()
+                .readonly_locks
+                .get(&native_loader::id())
+                .unwrap(),
+            1
+        );
+        // Non-program accounts remain writable
+        assert!(accounts
+            .account_locks
+            .lock()
+            .unwrap()
+            .write_locks
+            .contains(&keypair0.pubkey()));
+        assert!(accounts
+            .account_locks
+            .lock()
+            .unwrap()
+            .write_locks
+            .contains(&keypair1.pubkey()));
+    }
+
     #[test]
     fn test_collect_accounts_to_store() {
         let keypair0 = Keypair::new();
@@ -1991,6 +2075,7 @@ mod tests {
             &(Hash::default(), FeeCalculator::default()),
             true,
             true, // merge_nonce_error_into_system_error
+            true, // demote_program_write_locks
         );
         assert_eq!(collected_accounts.len(), 2);
         assert!(collected_accounts
@@ -2370,6 +2455,7 @@ mod tests {
             &(next_blockhash, FeeCalculator::default()),
             true,
             true, // merge_nonce_error_into_system_error
+            true, // demote_program_write_locks
         );
         assert_eq!(collected_accounts.len(), 2);
         assert_eq!(
@@ -2487,6 +2573,7 @@ mod tests {
             &(next_blockhash, FeeCalculator::default()),
             true,
             true, // merge_nonce_error_into_system_error
+            true, // demote_program_write_locks
         );
         assert_eq!(collected_accounts.len(), 1);
         let collected_nonce_account = collected_accounts
diff --git a/runtime/src/bank.rs b/runtime/src/bank.rs
index ed812e92c5..d3f1b1eda2 100644
--- a/runtime/src/bank.rs
+++ b/runtime/src/bank.rs
@@ -2755,7 +2755,10 @@ impl Bank {
             .into_iter()
             .map(SanitizedTransaction::try_from)
             .collect::<Result<Vec<_>>>()?;
-        let lock_results = self.rc.accounts.lock_accounts(sanitized_txs.iter());
+        let lock_results = self
+            .rc
+            .accounts
+            .lock_accounts(sanitized_txs.iter(), self.demote_program_write_locks());
         Ok(TransactionBatch::new(
             lock_results,
             self,
@@ -2775,7 +2778,10 @@ impl Bank {
                 })
             })
             .collect::<Result<Vec<_>>>()?;
-        let lock_results = self.rc.accounts.lock_accounts(sanitized_txs.iter());
+        let lock_results = self
+            .rc
+            .accounts
+            .lock_accounts(sanitized_txs.iter(), self.demote_program_write_locks());
         Ok(TransactionBatch::new(
             lock_results,
             self,
@@ -2788,7 +2794,10 @@ impl Bank {
         &'a self,
         txs: &'b [SanitizedTransaction],
     ) -> TransactionBatch<'a, 'b> {
-        let lock_results = self.rc.accounts.lock_accounts(txs.iter());
+        let lock_results = self
+            .rc
+            .accounts
+            .lock_accounts(txs.iter(), self.demote_program_write_locks());
         TransactionBatch::new(lock_results, self, Cow::Borrowed(txs))
     }
 
@@ -2863,9 +2872,11 @@ impl Bank {
     pub fn unlock_accounts(&self, batch: &mut TransactionBatch) {
         if batch.needs_unlock {
             batch.needs_unlock = false;
-            self.rc
-                .accounts
-                .unlock_accounts(batch.sanitized_transactions().iter(), batch.lock_results())
+            self.rc.accounts.unlock_accounts(
+                batch.sanitized_transactions().iter(),
+                batch.lock_results(),
+                self.demote_program_write_locks(),
+            )
         }
     }
 
@@ -3624,6 +3635,7 @@ impl Bank {
             &self.last_blockhash_with_fee_calculator(),
             self.rent_for_sysvars(),
             self.merge_nonce_error_into_system_error(),
+            self.demote_program_write_locks(),
         );
         let rent_debits = self.collect_rent(executed, loaded_txs);
 
@@ -5376,6 +5388,11 @@ impl Bank {
             .is_active(&feature_set::stake_program_advance_activating_credits_observed::id())
     }
 
+    pub fn demote_program_write_locks(&self) -> bool {
+        self.feature_set
+            .is_active(&feature_set::demote_program_write_locks::id())
+    }
+
     // Check if the wallclock time from bank creation to now has exceeded the allotted
     // time for transaction processing
     pub fn should_bank_still_be_processing_txs(
diff --git a/runtime/src/message_processor.rs b/runtime/src/message_processor.rs
index 06d1828cc7..864a196a71 100644
--- a/runtime/src/message_processor.rs
+++ b/runtime/src/message_processor.rs
@@ -10,7 +10,8 @@ use solana_sdk::{
     account::{AccountSharedData, ReadableAccount, WritableAccount},
     compute_budget::ComputeBudget,
     feature_set::{
-        neon_evm_compute_budget, tx_wide_compute_cap, updated_verify_policy, FeatureSet,
+        demote_program_write_locks, neon_evm_compute_budget, tx_wide_compute_cap,
+        updated_verify_policy, FeatureSet,
     },
     fee_calculator::FeeCalculator,
     hash::Hash,
@@ -94,6 +95,7 @@ impl<'a> ThisInvokeContext<'a> {
             instruction,
             executable_accounts,
             accounts,
+            feature_set.is_active(&demote_program_write_locks::id()),
         );
         let compute_meter = if feature_set.is_active(&tx_wide_compute_cap::id()) {
             compute_meter
@@ -389,6 +391,7 @@ impl MessageProcessor {
     }
 
     /// Verify the results of an instruction
+    #[allow(clippy::too_many_arguments)]
     pub fn verify(
         message: &Message,
         instruction: &CompiledInstruction,
@@ -399,6 +402,7 @@ impl MessageProcessor {
         timings: &mut ExecuteDetailsTimings,
         logger: Rc<RefCell<dyn Logger>>,
         updated_verify_policy: bool,
+        demote_program_write_locks: bool,
     ) -> Result<(), InstructionError> {
         // Verify all executable accounts have zero outstanding refs
         Self::verify_account_references(executable_accounts)?;
@@ -419,7 +423,7 @@ impl MessageProcessor {
                 pre_accounts[unique_index]
                     .verify(
                         program_id,
-                        message.is_writable(account_index),
+                        message.is_writable(account_index, demote_program_write_locks),
                         rent,
                         &account,
                         timings,
@@ -534,6 +538,7 @@ impl MessageProcessor {
             timings,
             invoke_context.get_logger(),
             invoke_context.is_feature_active(&updated_verify_policy::id()),
+            invoke_context.is_feature_active(&demote_program_write_locks::id()),
         )?;
 
         timings.accumulate(&invoke_context.timings);
@@ -713,7 +718,7 @@ mod tests {
                 ))),
             ));
             let write_privileges: Vec<bool> = (0..message.account_keys.len())
-                .map(|i| message.is_writable(i))
+                .map(|i| message.is_writable(i, /*demote_program_write_locks=*/ true))
                 .collect();
             invoke_context
                 .verify_and_update(&message.instructions[0], &these_accounts, &write_privileges)
@@ -1193,6 +1198,8 @@ mod tests {
             metas.clone(),
         );
         let message = Message::new(&[instruction], None);
+        let feature_set = FeatureSet::all_enabled();
+        let demote_program_write_locks = feature_set.is_active(&demote_program_write_locks::id());
 
         let ancestors = Ancestors::default();
         let blockhash = Hash::default();
@@ -1210,7 +1217,7 @@ mod tests {
             Rc::new(RefCell::new(MockComputeMeter::default())),
             Rc::new(RefCell::new(Executors::default())),
             None,
-            Arc::new(FeatureSet::all_enabled()),
+            Arc::new(feature_set),
             Arc::new(Accounts::default_for_tests()),
             &ancestors,
             &blockhash,
@@ -1222,7 +1229,7 @@ mod tests {
             .account_keys
             .iter()
             .enumerate()
-            .map(|(i, _)| message.is_writable(i))
+            .map(|(i, _)| message.is_writable(i, demote_program_write_locks))
             .collect::<Vec<bool>>();
         accounts[0].1.borrow_mut().data_as_mut_slice()[0] = 1;
         assert_eq!(
@@ -1282,7 +1289,7 @@ mod tests {
                 .account_keys
                 .iter()
                 .enumerate()
-                .map(|(i, _)| message.is_writable(i))
+                .map(|(i, _)| message.is_writable(i, demote_program_write_locks))
                 .collect::<Vec<bool>>();
             assert_eq!(
                 InstructionProcessor::process_cross_program_instruction(
diff --git a/sdk/benches/serialize_instructions.rs b/sdk/benches/serialize_instructions.rs
index 198e9ef0fa..2d639bf01f 100644
--- a/sdk/benches/serialize_instructions.rs
+++ b/sdk/benches/serialize_instructions.rs
@@ -15,6 +15,8 @@ fn make_instructions() -> Vec<Instruction> {
     vec![inst; 4]
 }
 
+const DEMOTE_PROGRAM_WRITE_LOCKS: bool = true;
+
 #[bench]
 fn bench_bincode_instruction_serialize(b: &mut Bencher) {
     let instructions = make_instructions();
@@ -30,7 +32,7 @@ fn bench_manual_instruction_serialize(b: &mut Bencher) {
         SanitizedMessage::try_from(Message::new(&instructions, Some(&Pubkey::new_unique())))
             .unwrap();
     b.iter(|| {
-        test::black_box(message.serialize_instructions());
+        test::black_box(message.serialize_instructions(DEMOTE_PROGRAM_WRITE_LOCKS));
     });
 }
 
@@ -49,7 +51,7 @@ fn bench_manual_instruction_deserialize(b: &mut Bencher) {
     let message =
         SanitizedMessage::try_from(Message::new(&instructions, Some(&Pubkey::new_unique())))
             .unwrap();
-    let serialized = message.serialize_instructions();
+    let serialized = message.serialize_instructions(DEMOTE_PROGRAM_WRITE_LOCKS);
     b.iter(|| {
         for i in 0..instructions.len() {
             test::black_box(instructions::load_instruction_at(i, &serialized).unwrap());
@@ -63,7 +65,7 @@ fn bench_manual_instruction_deserialize_single(b: &mut Bencher) {
     let message =
         SanitizedMessage::try_from(Message::new(&instructions, Some(&Pubkey::new_unique())))
             .unwrap();
-    let serialized = message.serialize_instructions();
+    let serialized = message.serialize_instructions(DEMOTE_PROGRAM_WRITE_LOCKS);
     b.iter(|| {
         test::black_box(instructions::load_instruction_at(3, &serialized).unwrap());
     });
diff --git a/sdk/program/src/message/legacy.rs b/sdk/program/src/message/legacy.rs
index 7279eb5e5f..21742b837d 100644
--- a/sdk/program/src/message/legacy.rs
+++ b/sdk/program/src/message/legacy.rs
@@ -353,7 +353,7 @@ impl Message {
         self.program_position(i).is_some()
     }
 
-    pub fn is_writable(&self, i: usize) -> bool {
+    pub fn is_writable(&self, i: usize, demote_program_write_locks: bool) -> bool {
         (i < (self.header.num_required_signatures - self.header.num_readonly_signed_accounts)
             as usize
             || (i >= self.header.num_required_signatures as usize
@@ -363,6 +363,7 @@ impl Message {
                 let key = self.account_keys[i];
                 sysvar::is_sysvar_id(&key) || BUILTIN_PROGRAMS_KEYS.contains(&key)
             }
+            && !(demote_program_write_locks && self.is_key_called_as_program(i))
     }
 
     pub fn is_signer(&self, i: usize) -> bool {
@@ -374,7 +375,7 @@ impl Message {
         let mut writable_keys = vec![];
         let mut readonly_keys = vec![];
         for (i, key) in self.account_keys.iter().enumerate() {
-            if self.is_writable(i) {
+            if self.is_writable(i, /*demote_program_write_locks=*/ true) {
                 writable_keys.push(key);
             } else {
                 readonly_keys.push(key);
@@ -412,7 +413,8 @@ impl Message {
             for account_index in &instruction.accounts {
                 let account_index = *account_index as usize;
                 let is_signer = self.is_signer(account_index);
-                let is_writable = self.is_writable(account_index);
+                let is_writable =
+                    self.is_writable(account_index, /*demote_program_write_locks=*/ true);
                 let mut meta_byte = 0;
                 if is_signer {
                     meta_byte |= 1 << Self::IS_SIGNER_BIT;
@@ -866,12 +868,13 @@ mod tests {
             recent_blockhash: Hash::default(),
             instructions: vec![],
         };
-        assert!(message.is_writable(0));
-        assert!(!message.is_writable(1));
-        assert!(!message.is_writable(2));
-        assert!(message.is_writable(3));
-        assert!(message.is_writable(4));
-        assert!(!message.is_writable(5));
+        let demote_program_write_locks = true;
+        assert!(message.is_writable(0, demote_program_write_locks));
+        assert!(!message.is_writable(1, demote_program_write_locks));
+        assert!(!message.is_writable(2, demote_program_write_locks));
+        assert!(message.is_writable(3, demote_program_write_locks));
+        assert!(message.is_writable(4, demote_program_write_locks));
+        assert!(!message.is_writable(5, demote_program_write_locks));
     }
 
     #[test]
diff --git a/sdk/program/src/message/mapped.rs b/sdk/program/src/message/mapped.rs
index 06be294df3..0f30e35238 100644
--- a/sdk/program/src/message/mapped.rs
+++ b/sdk/program/src/message/mapped.rs
@@ -4,7 +4,7 @@ use {
         pubkey::Pubkey,
         sysvar,
     },
-    std::collections::HashSet,
+    std::{collections::HashSet, convert::TryFrom},
 };
 
 /// Combination of a version #0 message and its mapped addresses
@@ -96,20 +96,32 @@ impl MappedMessage {
     }
 
     /// Returns true if the account at the specified index was loaded as writable
-    pub fn is_writable(&self, key_index: usize) -> bool {
+    pub fn is_writable(&self, key_index: usize, demote_program_write_locks: bool) -> bool {
         if self.is_writable_index(key_index) {
             if let Some(key) = self.get_account_key(key_index) {
-                return !(sysvar::is_sysvar_id(key) || BUILTIN_PROGRAMS_KEYS.contains(key));
+                return !(sysvar::is_sysvar_id(key) || BUILTIN_PROGRAMS_KEYS.contains(key)
+                    || (demote_program_write_locks && self.is_key_called_as_program(key_index)));
             }
         }
         false
     }
+
+    /// Returns true if the account at the specified index is called as a program by an instruction
+    pub fn is_key_called_as_program(&self, key_index: usize) -> bool {
+        if let Ok(key_index) = u8::try_from(key_index) {
+            self.message.instructions
+                .iter()
+                .any(|ix| ix.program_id_index == key_index)
+        } else {
+            false
+        }
+    }
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::{message::MessageHeader, system_program, sysvar};
+    use crate::{instruction::CompiledInstruction, message::MessageHeader, system_program, sysvar};
     use itertools::Itertools;
 
     fn create_test_mapped_message() -> (MappedMessage, [Pubkey; 6]) {
@@ -236,10 +248,42 @@ mod tests {
 
         mapped_msg.message.account_keys[0] = sysvar::clock::id();
         assert!(mapped_msg.is_writable_index(0));
-        assert!(!mapped_msg.is_writable(0));
+        assert!(!mapped_msg.is_writable(0, /*demote_program_write_locks=*/ true));
 
         mapped_msg.message.account_keys[0] = system_program::id();
         assert!(mapped_msg.is_writable_index(0));
-        assert!(!mapped_msg.is_writable(0));
+        assert!(!mapped_msg.is_writable(0, /*demote_program_write_locks=*/ true));
+    }
+
+    #[test]
+    fn test_demote_writable_program() {
+        let key0 = Pubkey::new_unique();
+        let key1 = Pubkey::new_unique();
+        let key2 = Pubkey::new_unique();
+        let mapped_msg = MappedMessage {
+            message: v0::Message {
+                header: MessageHeader {
+                    num_required_signatures: 1,
+                    num_readonly_signed_accounts: 0,
+                    num_readonly_unsigned_accounts: 0,
+                },
+                account_keys: vec![key0],
+                instructions: vec![
+                    CompiledInstruction {
+                        program_id_index: 2,
+                        accounts: vec![1],
+                        data: vec![],
+                    }
+                ],
+                ..v0::Message::default()
+            },
+            mapped_addresses: MappedAddresses {
+                writable: vec![key1, key2],
+                readonly: vec![],
+            },
+        };
+
+        assert!(mapped_msg.is_writable_index(2));
+        assert!(!mapped_msg.is_writable(2, /*demote_program_write_locks=*/ true));
     }
 }
diff --git a/sdk/program/src/message/sanitized.rs b/sdk/program/src/message/sanitized.rs
index 551bee22f8..3b8d3d7975 100644
--- a/sdk/program/src/message/sanitized.rs
+++ b/sdk/program/src/message/sanitized.rs
@@ -175,12 +175,9 @@ impl SanitizedMessage {
     /// Returns true if the account at the specified index is invoked as a
     /// program in this message.
     pub fn is_invoked(&self, key_index: usize) -> bool {
-        if let Ok(key_index) = u8::try_from(key_index) {
-            self.instructions()
-                .iter()
-                .any(|ix| ix.program_id_index == key_index)
-        } else {
-            false
+        match self {
+            Self::Legacy(message) => message.is_key_called_as_program(key_index),
+            Self::V0(message) => message.is_key_called_as_program(key_index),
         }
     }
 
@@ -192,10 +189,10 @@ impl SanitizedMessage {
 
     /// Returns true if the account at the specified index is writable by the
     /// instructions in this message.
-    pub fn is_writable(&self, index: usize) -> bool {
+    pub fn is_writable(&self, index: usize, demote_program_write_locks: bool) -> bool {
         match self {
-            Self::Legacy(message) => message.is_writable(index),
-            Self::V0(message) => message.is_writable(index),
+            Self::Legacy(message) => message.is_writable(index, demote_program_write_locks),
+            Self::V0(message) => message.is_writable(index, demote_program_write_locks),
         }
     }
 
@@ -219,7 +216,7 @@ impl SanitizedMessage {
     //   67..69 - data len - u16
     //   69..data_len - data
     #[allow(clippy::integer_arithmetic)]
-    pub fn serialize_instructions(&self) -> Vec<u8> {
+    pub fn serialize_instructions(&self, demote_program_write_locks: bool) -> Vec<u8> {
         // 64 bytes is a reasonable guess, calculating exactly is slower in benchmarks
         let mut data = Vec::with_capacity(self.instructions().len() * (32 * 2));
         append_u16(&mut data, self.instructions().len() as u16);
@@ -234,7 +231,7 @@ impl SanitizedMessage {
             for account_index in &instruction.accounts {
                 let account_index = *account_index as usize;
                 let is_signer = self.is_signer(account_index);
-                let is_writable = self.is_writable(account_index);
+                let is_writable = self.is_writable(account_index, demote_program_write_locks);
                 let mut account_meta = InstructionsSysvarAccountMeta::NONE;
                 if is_signer {
                     account_meta |= InstructionsSysvarAccountMeta::IS_SIGNER;
@@ -440,9 +437,10 @@ mod tests {
             ),
         ];
 
+        let demote_program_write_locks = true;
         let message = Message::new(&instructions, Some(&id1));
         let sanitized_message = SanitizedMessage::try_from(message.clone()).unwrap();
-        let serialized = sanitized_message.serialize_instructions();
+        let serialized = sanitized_message.serialize_instructions(demote_program_write_locks);
 
         // assert that SanitizedMessage::serialize_instructions has the same behavior as the
         // deprecated Message::serialize_instructions method
diff --git a/sdk/src/feature_set.rs b/sdk/src/feature_set.rs
index ef50407d2d..fd3313e66f 100644
--- a/sdk/src/feature_set.rs
+++ b/sdk/src/feature_set.rs
@@ -191,6 +191,10 @@ pub mod stake_program_advance_activating_credits_observed {
     solana_sdk::declare_id!("SAdVFw3RZvzbo6DvySbSdBnHN4gkzSTH9dSxesyKKPj");
 }
 
+pub mod demote_program_write_locks {
+    solana_sdk::declare_id!("3E3jV7v9VcdJL8iYZUMax9DiDno8j7EWUVbhm9RtShj2");
+}
+
 lazy_static! {
     /// Map of feature identifiers to user-visible description
     pub static ref FEATURE_NAMES: HashMap<Pubkey, &'static str> = [
@@ -234,6 +238,7 @@ lazy_static! {
         (instructions_sysvar_owned_by_sysvar::id(), "fix owner for instructions sysvar"),
         (close_upgradeable_program_accounts::id(), "enable closing upgradeable program accounts"),
         (stake_program_advance_activating_credits_observed::id(), "Enable advancing credits observed for activation epoch #19309"),
+        (demote_program_write_locks::id(), "demote program write locks to readonly #19593"),
         /*************** ADD NEW FEATURES HERE ***************/
     ]
     .iter()
diff --git a/sdk/src/transaction/sanitized.rs b/sdk/src/transaction/sanitized.rs
index 592468988d..d3ffc77af6 100644
--- a/sdk/src/transaction/sanitized.rs
+++ b/sdk/src/transaction/sanitized.rs
@@ -125,7 +125,7 @@ impl SanitizedTransaction {
     }
 
     /// Return the list of accounts that must be locked during processing this transaction.
-    pub fn get_account_locks(&self) -> TransactionAccountLocks {
+    pub fn get_account_locks(&self, demote_program_write_locks: bool) -> TransactionAccountLocks {
         let message = &self.message;
         let num_readonly_accounts = message.num_readonly_accounts();
         let num_writable_accounts = message
@@ -138,7 +138,7 @@ impl SanitizedTransaction {
         };
 
         for (i, key) in message.account_keys_iter().enumerate() {
-            if message.is_writable(i) {
+            if message.is_writable(i, demote_program_write_locks) {
                 account_locks.writable.push(key);
             } else {
                 account_locks.readonly.push(key);
diff --git a/transaction-status/src/parse_accounts.rs b/transaction-status/src/parse_accounts.rs
index ebef018e71..197643450b 100644
--- a/transaction-status/src/parse_accounts.rs
+++ b/transaction-status/src/parse_accounts.rs
@@ -13,7 +13,7 @@ pub fn parse_accounts(message: &Message) -> Vec<ParsedAccount> {
     for (i, account_key) in message.account_keys.iter().enumerate() {
         accounts.push(ParsedAccount {
             pubkey: account_key.to_string(),
-            writable: message.is_writable(i),
+            writable: message.is_writable(i, /*demote_program_write_locks=*/ true),
             signer: message.is_signer(i),
         });
     }