diff --git a/learning-examples/manual_buy.py b/learning-examples/manual_buy.py
index 9a2c889..1622d91 100644
--- a/learning-examples/manual_buy.py
+++ b/learning-examples/manual_buy.py
@@ -3,6 +3,7 @@ import base64
 import hashlib
 import json
 import os
+import random
 import struct
 
 import base58
@@ -43,6 +44,20 @@ SYSTEM_ASSOCIATED_TOKEN_ACCOUNT_PROGRAM = Pubkey.from_string(
 SOL = Pubkey.from_string("So11111111111111111111111111111111111111112")
 LAMPORTS_PER_SOL = 1_000_000_000
 
+# 8 breaking-upgrade fee recipients (pump.fun program upgrade 2026-04-28).
+# One must be appended (mutable) AFTER bonding-curve-v2 on every buy/sell.
+# Doc: github.com/pump-fun/pump-public-docs/blob/main/docs/BREAKING_FEE_RECIPIENT.md
+BREAKING_FEE_RECIPIENTS = [
+    Pubkey.from_string("5YxQFdt3Tr9zJLvkFccqXVUwhdTWJQc1fFg2YPbxvxeD"),
+    Pubkey.from_string("9M4giFFMxmFGXtc3feFzRai56WbBqehoSeRE5GK7gf7"),
+    Pubkey.from_string("GXPFM2caqTtQYC2cJ5yJRi9VDkpsYZXzYdwYpGnLmtDL"),
+    Pubkey.from_string("3BpXnfJaUTiwXnJNe7Ej1rcbzqTTQUvLShZaWazebsVR"),
+    Pubkey.from_string("5cjcW9wExnJJiqgLjq7DEG75Pm6JBgE1hNv4B2vHXUW6"),
+    Pubkey.from_string("EHAAiTxcdDwQ3U4bU6YcMsQGaekdzLS3B5SmYo46kJtL"),
+    Pubkey.from_string("5eHhjP8JaYkz83CWwvGU2uMUXefd3AazWGx4gpcuEEYD"),
+    Pubkey.from_string("A7hAgCzFw14fejgCp387JUJRMNyz4j89JKnhtKU8piqW"),
+]
+
 # RPC ENDPOINTS
 RPC_ENDPOINT = os.environ.get("SOLANA_NODE_RPC_ENDPOINT")
 RPC_WEBSOCKET = os.environ.get("SOLANA_NODE_WSS_ENDPOINT")
@@ -295,6 +310,12 @@ async def buy_token(
                 is_signer=False,
                 is_writable=False,
             ),
+            # 18th account: breaking-upgrade fee recipient (mutable) — required from 2026-04-28
+            AccountMeta(
+                pubkey=random.choice(BREAKING_FEE_RECIPIENTS),
+                is_signer=False,
+                is_writable=True,
+            ),
         ]
 
         discriminator = struct.pack("<Q", 16927863322537952870)
@@ -359,16 +380,24 @@ def decode_create_instruction(ix_data, ix_def, accounts):
     offset = 8  # Skip 8-byte discriminator
 
     for arg in ix_def["args"]:
-        if arg["type"] == "string":
+        t = arg["type"]
+        if t == "string":
             length = struct.unpack_from("<I", ix_data, offset)[0]
             offset += 4
             value = ix_data[offset : offset + length].decode("utf-8")
             offset += length
-        elif arg["type"] == "pubkey":
+        elif t == "pubkey":
             value = base58.b58encode(ix_data[offset : offset + 32]).decode("utf-8")
             offset += 32
+        elif t == "bool":
+            value = bool(ix_data[offset])
+            offset += 1
+        elif isinstance(t, dict) and "defined" in t:
+            # OptionBool = struct { bool } = 1 byte
+            value = bool(ix_data[offset])
+            offset += 1
         else:
-            raise ValueError(f"Unsupported type: {arg['type']}")
+            raise ValueError(f"Unsupported type: {t}")
 
         args[arg["name"]] = value
 
@@ -457,12 +486,14 @@ async def listen_for_create_transaction():
                                                     for instr in idl["instructions"]
                                                     if instr["name"] == instruction_name
                                                 )
+                                                # Skip txs that use Address Lookup Tables — their
+                                                # instruction account indices reference ALT-loaded keys
+                                                # not present in transaction.message.account_keys.
+                                                static_keys = transaction.message.account_keys
+                                                if any(idx >= len(static_keys) for idx in ix.accounts):
+                                                    continue
                                                 account_keys = [
-                                                    str(
-                                                        transaction.message.account_keys[
-                                                            index
-                                                        ]
-                                                    )
+                                                    str(static_keys[index])
                                                     for index in ix.accounts
                                                 ]
                                                 decoded_args = (
diff --git a/learning-examples/manual_buy_cu_optimized.py b/learning-examples/manual_buy_cu_optimized.py
index cc6ed44..6af2faf 100644
--- a/learning-examples/manual_buy_cu_optimized.py
+++ b/learning-examples/manual_buy_cu_optimized.py
@@ -22,6 +22,7 @@ import base64
 import hashlib
 import json
 import os
+import random
 import struct
 
 import base58
@@ -53,6 +54,20 @@ PUMP_EVENT_AUTHORITY = Pubkey.from_string(
 )
 PUMP_FEE = Pubkey.from_string("CebN5WGQ4jvEPvsVU4EoHEpgzq1VV7AbicfhtW4xC9iM")
 PUMP_FEE_PROGRAM = Pubkey.from_string("pfeeUxB6jkeY1Hxd7CsFCAjcbHA9rWtchMGdZ6VojVZ")
+
+# 8 breaking-upgrade fee recipients (pump.fun program upgrade 2026-04-28).
+# One must be appended (mutable) AFTER bonding-curve-v2 on every buy/sell.
+# Doc: github.com/pump-fun/pump-public-docs/blob/main/docs/BREAKING_FEE_RECIPIENT.md
+BREAKING_FEE_RECIPIENTS = [
+    Pubkey.from_string("5YxQFdt3Tr9zJLvkFccqXVUwhdTWJQc1fFg2YPbxvxeD"),
+    Pubkey.from_string("9M4giFFMxmFGXtc3feFzRai56WbBqehoSeRE5GK7gf7"),
+    Pubkey.from_string("GXPFM2caqTtQYC2cJ5yJRi9VDkpsYZXzYdwYpGnLmtDL"),
+    Pubkey.from_string("3BpXnfJaUTiwXnJNe7Ej1rcbzqTTQUvLShZaWazebsVR"),
+    Pubkey.from_string("5cjcW9wExnJJiqgLjq7DEG75Pm6JBgE1hNv4B2vHXUW6"),
+    Pubkey.from_string("EHAAiTxcdDwQ3U4bU6YcMsQGaekdzLS3B5SmYo46kJtL"),
+    Pubkey.from_string("5eHhjP8JaYkz83CWwvGU2uMUXefd3AazWGx4gpcuEEYD"),
+    Pubkey.from_string("A7hAgCzFw14fejgCp387JUJRMNyz4j89JKnhtKU8piqW"),
+]
 SYSTEM_PROGRAM = Pubkey.from_string("11111111111111111111111111111111")
 SYSTEM_TOKEN_PROGRAM = Pubkey.from_string("TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA")
 TOKEN_2022_PROGRAM = Pubkey.from_string("TokenzQdBNbLqP5VEhdkAS6EPFLC1PHnBqCXEpPxuEb")
@@ -333,6 +348,12 @@ async def buy_token(
                 is_signer=False,
                 is_writable=False,
             ),
+            # 18th account: breaking-upgrade fee recipient (mutable) — required from 2026-04-28
+            AccountMeta(
+                pubkey=random.choice(BREAKING_FEE_RECIPIENTS),
+                is_signer=False,
+                is_writable=True,
+            ),
         ]
 
         discriminator = struct.pack("<Q", 16927863322537952870)
@@ -350,7 +371,10 @@ async def buy_token(
         # CU OPTIMIZATION: Limit account data to 512KB (down from 64MB default)
         # This reduces CU cost from 16k to ~128 CU and improves tx priority.
         # Must be placed FIRST in the instruction list.
-        cu_limit_ix = set_loaded_accounts_data_size_limit(512_000)
+        # 16MB limit: works for cashback-coin Token-2022 buys on mainnet.
+        # Smaller values (4–8MB) trigger MaxLoadedAccountsDataSizeExceeded for
+        # Token-2022 mints with extensions. Still 4× smaller than the 64MB default.
+        cu_limit_ix = set_loaded_accounts_data_size_limit(16_384_000)
 
         msg = Message(
             [cu_limit_ix, set_compute_unit_price(1_000), idempotent_ata_ix, buy_ix],
@@ -402,16 +426,21 @@ def decode_create_instruction(ix_data, ix_def, accounts):
     args = {}
     offset = 8
     for arg in ix_def["args"]:
-        if arg["type"] == "string":
+        t = arg["type"]
+        if t == "string":
             length = struct.unpack_from("<I", ix_data, offset)[0]
             offset += 4
             value = ix_data[offset : offset + length].decode("utf-8")
             offset += length
-        elif arg["type"] == "pubkey":
+        elif t == "pubkey":
             value = base58.b58encode(ix_data[offset : offset + 32]).decode("utf-8")
             offset += 32
+        elif t == "bool" or (isinstance(t, dict) and "defined" in t):
+            # `bool` and `OptionBool` (struct {bool}) both serialize as 1 byte
+            value = bool(ix_data[offset])
+            offset += 1
         else:
-            raise ValueError(f"Unsupported type: {arg['type']}")
+            raise ValueError(f"Unsupported type: {t}")
         args[arg["name"]] = value
 
     args["mint"] = str(accounts[0])
@@ -499,6 +528,12 @@ async def listen_for_create_transaction():
                                                     for instr in idl["instructions"]
                                                     if instr["name"] == instruction_name
                                                 )
+                                                # Skip txs that use Address Lookup Tables — their
+                                                # instruction account indices reference ALT-loaded keys
+                                                # not present in transaction.message.account_keys.
+                                                static_keys = transaction.message.account_keys
+                                                if any(idx >= len(static_keys) for idx in ix.accounts):
+                                                    continue
                                                 account_keys = [
                                                     str(
                                                         transaction.message.account_keys[
@@ -554,7 +589,7 @@ async def main():
     print(
         f"Buying {amount:.6f} SOL worth of the new token with {slippage * 100:.1f}% slippage tolerance..."
     )
-    print("CU Optimization: Enabled (512KB account data limit)")
+    print("CU Optimization: Enabled (16MB account data limit)")
     await buy_token(
         mint,
         bonding_curve,
diff --git a/learning-examples/manual_buy_geyser.py b/learning-examples/manual_buy_geyser.py
index b6b3b62..42d07cb 100644
--- a/learning-examples/manual_buy_geyser.py
+++ b/learning-examples/manual_buy_geyser.py
@@ -1,6 +1,7 @@
 import asyncio
 import json
 import os
+import random
 import struct
 import sys
 
@@ -39,6 +40,20 @@ PUMP_EVENT_AUTHORITY = Pubkey.from_string(
 )
 PUMP_FEE = Pubkey.from_string("CebN5WGQ4jvEPvsVU4EoHEpgzq1VV7AbicfhtW4xC9iM")
 PUMP_FEE_PROGRAM = Pubkey.from_string("pfeeUxB6jkeY1Hxd7CsFCAjcbHA9rWtchMGdZ6VojVZ")
+
+# 8 breaking-upgrade fee recipients (pump.fun program upgrade 2026-04-28).
+# One must be appended (mutable) AFTER bonding-curve-v2 on every buy/sell.
+# Doc: github.com/pump-fun/pump-public-docs/blob/main/docs/BREAKING_FEE_RECIPIENT.md
+BREAKING_FEE_RECIPIENTS = [
+    Pubkey.from_string("5YxQFdt3Tr9zJLvkFccqXVUwhdTWJQc1fFg2YPbxvxeD"),
+    Pubkey.from_string("9M4giFFMxmFGXtc3feFzRai56WbBqehoSeRE5GK7gf7"),
+    Pubkey.from_string("GXPFM2caqTtQYC2cJ5yJRi9VDkpsYZXzYdwYpGnLmtDL"),
+    Pubkey.from_string("3BpXnfJaUTiwXnJNe7Ej1rcbzqTTQUvLShZaWazebsVR"),
+    Pubkey.from_string("5cjcW9wExnJJiqgLjq7DEG75Pm6JBgE1hNv4B2vHXUW6"),
+    Pubkey.from_string("EHAAiTxcdDwQ3U4bU6YcMsQGaekdzLS3B5SmYo46kJtL"),
+    Pubkey.from_string("5eHhjP8JaYkz83CWwvGU2uMUXefd3AazWGx4gpcuEEYD"),
+    Pubkey.from_string("A7hAgCzFw14fejgCp387JUJRMNyz4j89JKnhtKU8piqW"),
+]
 SYSTEM_PROGRAM = Pubkey.from_string("11111111111111111111111111111111")
 SYSTEM_TOKEN_PROGRAM = Pubkey.from_string("TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA")
 SYSTEM_TOKEN_2022_PROGRAM = Pubkey.from_string(
@@ -365,19 +380,11 @@ async def buy_token(
         )
         amount_lamports = int(amount * LAMPORTS_PER_SOL)
 
-        # Fetch bonding curve state to calculate price and determine fee recipient
-        # NOTE: Price calculation is commented out to speed up testing - using fixed values
-        # For production, uncomment the lines below to:
-        # 1. Calculate proper token amounts based on current price
-        # 2. Detect mayhem mode and use correct fee recipient
-        # curve_state = await get_pump_curve_state(client, bonding_curve)
-        # token_price_sol = calculate_pump_curve_price(curve_state)
-        # token_amount = amount / token_price_sol
-        # fee_recipient = await get_fee_recipient(client, curve_state)
-
-        # Testing values - replace with code above for production
-        token_amount = 100  # Fixed token amount
-        fee_recipient = PUMP_FEE  # Standard fee recipient (doesn't detect mayhem mode)
+        # Fetch bonding curve state for price + mayhem-mode-aware fee recipient.
+        curve_state = await get_pump_curve_state(client, bonding_curve)
+        token_price_sol = calculate_pump_curve_price(curve_state)
+        token_amount = amount / token_price_sol
+        fee_recipient = await get_fee_recipient(client, curve_state)
 
         # Calculate maximum SOL to spend with slippage
         max_amount_lamports = int(amount_lamports * (1 + slippage))
@@ -433,6 +440,12 @@ async def buy_token(
                 is_signer=False,
                 is_writable=False,
             ),
+            # 18th account: breaking-upgrade fee recipient (mutable) — required from 2026-04-28
+            AccountMeta(
+                pubkey=random.choice(BREAKING_FEE_RECIPIENTS),
+                is_signer=False,
+                is_writable=True,
+            ),
         ]
 
         discriminator = struct.pack("<Q", 16927863322537952870)
diff --git a/learning-examples/manual_sell.py b/learning-examples/manual_sell.py
index 37da5d8..3421fee 100644
--- a/learning-examples/manual_sell.py
+++ b/learning-examples/manual_sell.py
@@ -1,6 +1,8 @@
 import asyncio
 import os
+import random
 import struct
+import sys
 
 import base58
 from construct import Flag, Int64ul, Struct
@@ -18,7 +20,7 @@ from spl.token.instructions import get_associated_token_address
 # Here and later all the discriminators are precalculated. See learning-examples/calculate_discriminator.py
 EXPECTED_DISCRIMINATOR = struct.pack("<Q", 6966180631402821399)
 TOKEN_DECIMALS = 6
-TOKEN_MINT = Pubkey.from_string("...")  # Replace with actual token mint address
+TOKEN_MINT = Pubkey.from_string(sys.argv[1] if len(sys.argv) > 1 else "...")  # Pass mint as argv[1] or hardcode here
 
 # Global constants
 PUMP_PROGRAM = Pubkey.from_string("6EF8rrecthR5Dkzon8Nwu78hRvfCKubJ14M5uBEwF6P")
@@ -42,6 +44,20 @@ UNIT_BUDGET = 100_000
 
 RPC_ENDPOINT = os.environ.get("SOLANA_NODE_RPC_ENDPOINT")
 
+# 8 breaking-upgrade fee recipients (pump.fun program upgrade 2026-04-28).
+# One must be appended (mutable) AFTER bonding-curve-v2 on every buy/sell.
+# Doc: github.com/pump-fun/pump-public-docs/blob/main/docs/BREAKING_FEE_RECIPIENT.md
+BREAKING_FEE_RECIPIENTS = [
+    Pubkey.from_string("5YxQFdt3Tr9zJLvkFccqXVUwhdTWJQc1fFg2YPbxvxeD"),
+    Pubkey.from_string("9M4giFFMxmFGXtc3feFzRai56WbBqehoSeRE5GK7gf7"),
+    Pubkey.from_string("GXPFM2caqTtQYC2cJ5yJRi9VDkpsYZXzYdwYpGnLmtDL"),
+    Pubkey.from_string("3BpXnfJaUTiwXnJNe7Ej1rcbzqTTQUvLShZaWazebsVR"),
+    Pubkey.from_string("5cjcW9wExnJJiqgLjq7DEG75Pm6JBgE1hNv4B2vHXUW6"),
+    Pubkey.from_string("EHAAiTxcdDwQ3U4bU6YcMsQGaekdzLS3B5SmYo46kJtL"),
+    Pubkey.from_string("5eHhjP8JaYkz83CWwvGU2uMUXefd3AazWGx4gpcuEEYD"),
+    Pubkey.from_string("A7hAgCzFw14fejgCp387JUJRMNyz4j89JKnhtKU8piqW"),
+]
+
 
 class BondingCurveState:
     """Bonding curve state parser with progressive field parsing.
@@ -95,9 +111,16 @@ class BondingCurveState:
         # Parse mayhem mode flag if bytes remaining (added in V3)
         if len(data) >= offset + 1:
             self.is_mayhem_mode = bool(data[offset])
+            offset += 1
         else:
             self.is_mayhem_mode = False
 
+        # Parse cashback flag if bytes remaining (added in V4 — late-Feb 2026 cashback upgrade)
+        if len(data) >= offset + 1:
+            self.is_cashback_coin = bool(data[offset])
+        else:
+            self.is_cashback_coin = False
+
 
 async def get_pump_curve_state(
     conn: AsyncClient, curve_address: Pubkey
@@ -155,6 +178,14 @@ def _find_bonding_curve_v2(mint: Pubkey) -> Pubkey:
     return derived_address
 
 
+def _find_user_volume_accumulator(user: Pubkey) -> Pubkey:
+    derived_address, _ = Pubkey.find_program_address(
+        [b"user_volume_accumulator", bytes(user)],
+        PUMP_PROGRAM,
+    )
+    return derived_address
+
+
 async def get_fee_recipient(
     client: AsyncClient, curve_state: BondingCurveState
 ) -> Pubkey:
@@ -320,13 +351,31 @@ async def sell_token(
                 is_signer=False,
                 is_writable=False,
             ),
-            # Remaining account: bonding_curve_v2 (readonly, required for all coins)
+        ]
+        # For cashback coins, insert user_volume_accumulator before bonding-curve-v2 (17 accounts total).
+        if curve_state.is_cashback_coin:
+            accounts.append(
+                AccountMeta(
+                    pubkey=_find_user_volume_accumulator(payer.pubkey()),
+                    is_signer=False,
+                    is_writable=True,
+                )
+            )
+        accounts.extend([
+            # bonding_curve_v2 (readonly, required for all coins)
             AccountMeta(
                 pubkey=_find_bonding_curve_v2(mint),
                 is_signer=False,
                 is_writable=False,
             ),
-        ]
+            # Breaking-upgrade fee recipient (mutable) — required from 2026-04-28.
+            # 16 accounts non-cashback / 17 accounts cashback.
+            AccountMeta(
+                pubkey=random.choice(BREAKING_FEE_RECIPIENTS),
+                is_signer=False,
+                is_writable=True,
+            ),
+        ])
 
         discriminator = struct.pack("<Q", 12502976635542562355)
         # Encode OptionBool for track_volume: [1, 1] = Some(true)