diff --git a/Cargo.lock b/Cargo.lock
index 6486d9df8..53a06919d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3156,6 +3156,7 @@ dependencies = [
  "async-trait",
  "base64 0.13.0",
  "bincode",
+ "borsh",
  "bytemuck",
  "checked_math",
  "env_logger 0.9.0",
diff --git a/programs/mango-v4/Cargo.toml b/programs/mango-v4/Cargo.toml
index 0a58ebc99..a6cfe6349 100644
--- a/programs/mango-v4/Cargo.toml
+++ b/programs/mango-v4/Cargo.toml
@@ -25,6 +25,7 @@ anchor-lang = { path = "../../anchor/lang" }
 anchor-spl = { path = "../../anchor/spl" }
 arrayref = "0.3.6"
 bincode = "1.3.3"
+borsh = { version = "0.9.3", features = ["const-generics"] }
 bytemuck = "^1.7.2"
 checked_math = { path = "../../lib/checked_math" }
 fixed = { version = "=1.11.0", features = ["serde", "borsh"] } # todo: higher versions don't work
diff --git a/programs/mango-v4/src/error.rs b/programs/mango-v4/src/error.rs
index 7ef6d279d..53b411399 100644
--- a/programs/mango-v4/src/error.rs
+++ b/programs/mango-v4/src/error.rs
@@ -7,6 +7,8 @@ use core::fmt::Display;
 pub enum MangoError {
     #[msg("")]
     SomeError,
+    #[msg("")]
+    NotImplementedError,
     #[msg("checked math error")]
     MathError,
     #[msg("")]
diff --git a/programs/mango-v4/src/instructions/perp_create_market.rs b/programs/mango-v4/src/instructions/perp_create_market.rs
index ea01edd4a..80d5c52c5 100644
--- a/programs/mango-v4/src/instructions/perp_create_market.rs
+++ b/programs/mango-v4/src/instructions/perp_create_market.rs
@@ -96,8 +96,9 @@ pub fn perp_create_market(
         base_token_decimals,
         perp_market_index,
         base_token_index: base_token_index_opt.ok_or(TokenIndex::MAX).unwrap(),
-        padding: Default::default(),
-        reserved: Default::default(),
+        padding1: Default::default(),
+        padding2: Default::default(),
+        reserved: [0; 128],
     };
 
     let mut bids = ctx.accounts.bids.load_init()?;
diff --git a/programs/mango-v4/src/instructions/serum3_register_market.rs b/programs/mango-v4/src/instructions/serum3_register_market.rs
index a8db144ee..aa0fc0e75 100644
--- a/programs/mango-v4/src/instructions/serum3_register_market.rs
+++ b/programs/mango-v4/src/instructions/serum3_register_market.rs
@@ -75,8 +75,9 @@ pub fn serum3_register_market(
         base_token_index: base_bank.token_index,
         quote_token_index: quote_bank.token_index,
         bump: *ctx.bumps.get("serum_market").ok_or(MangoError::SomeError)?,
-        padding: Default::default(),
-        reserved: Default::default(),
+        padding1: Default::default(),
+        padding2: Default::default(),
+        reserved: [0; 128],
     };
 
     Ok(())
diff --git a/programs/mango-v4/src/instructions/token_register.rs b/programs/mango-v4/src/instructions/token_register.rs
index aa152efb7..51db22576 100644
--- a/programs/mango-v4/src/instructions/token_register.rs
+++ b/programs/mango-v4/src/instructions/token_register.rs
@@ -154,7 +154,8 @@ pub fn token_register(
         bump: *ctx.bumps.get("bank").ok_or(MangoError::SomeError)?,
         mint_decimals: ctx.accounts.mint.decimals,
         bank_num: 0,
-        reserved: Default::default(),
+        padding: Default::default(),
+        reserved: [0; 256],
     };
 
     // TODO: ALTs are unavailable
@@ -174,8 +175,9 @@ pub fn token_register(
         token_index,
         address_lookup_table_bank_index: alt_previous_size as u8,
         address_lookup_table_oracle_index: alt_previous_size as u8 + 1,
-        padding: Default::default(),
-        reserved: Default::default(),
+        padding1: Default::default(),
+        padding2: Default::default(),
+        reserved: [0; 256],
     };
 
     mint_info.banks[0] = ctx.accounts.bank.key();
diff --git a/programs/mango-v4/src/state/bank.rs b/programs/mango-v4/src/state/bank.rs
index 6033a7321..177df3bb4 100644
--- a/programs/mango-v4/src/state/bank.rs
+++ b/programs/mango-v4/src/state/bank.rs
@@ -91,15 +91,15 @@ pub struct Bank {
 
     pub mint_decimals: u8,
 
-    pub reserved: [u8; 4],
+    pub padding: [u8; 4],
 
     pub bank_num: u64,
-    // TODO: add space for an oracle which services interest rate for the bank's mint
-    // interest rate tied to oracle might help reduce spreads between deposits and borrows
+
+    pub reserved: [u8; 256],
 }
 const_assert_eq!(
     size_of::<Bank>(),
-    16 + 32 * 4 + 8 * 2 + 16 * 23 + 2 * 8 + 2 + 1 + 1 + 4 + 8
+    16 + 32 * 4 + 8 * 2 + 16 * 23 + 2 * 8 + 2 + 1 + 1 + 4 + 8 + 256
 );
 const_assert_eq!(size_of::<Bank>() % 8, 0);
 
@@ -190,7 +190,8 @@ impl Bank {
             token_index: existing_bank.token_index,
             bump: existing_bank.bump,
             mint_decimals: existing_bank.mint_decimals,
-            reserved: Default::default(),
+            padding: Default::default(),
+            reserved: [0; 256],
             bank_num,
         }
     }
@@ -591,7 +592,8 @@ mod tests {
                     indexed_position: I80F48::ZERO,
                     token_index: 0,
                     in_use_count: if is_in_use { 1 } else { 0 },
-                    reserved: Default::default(),
+                    padding: Default::default(),
+                    reserved: [0; 40],
                 };
 
                 account.indexed_position = indexed(I80F48::from_num(start), &bank);
diff --git a/programs/mango-v4/src/state/group.rs b/programs/mango-v4/src/state/group.rs
index e19d6b754..5fa039de9 100644
--- a/programs/mango-v4/src/state/group.rs
+++ b/programs/mango-v4/src/state/group.rs
@@ -32,9 +32,10 @@ pub struct Group {
     pub version: u8,
 
     pub padding2: [u8; 5],
-    pub reserved: [u8; 8],
+
+    pub reserved: [u8; 256],
 }
-const_assert_eq!(size_of::<Group>(), 32 * 5 + 4 + 4 + 1 * 2 + 6 + 8);
+const_assert_eq!(size_of::<Group>(), 32 * 5 + 4 + 4 + 1 * 2 + 6 + 256);
 const_assert_eq!(size_of::<Group>() % 8, 0);
 
 impl Group {
diff --git a/programs/mango-v4/src/state/mango_account.rs b/programs/mango-v4/src/state/mango_account.rs
index 4cba2e328..a87ee54fe 100644
--- a/programs/mango-v4/src/state/mango_account.rs
+++ b/programs/mango-v4/src/state/mango_account.rs
@@ -31,6 +31,7 @@ use checked_math as cm;
 type BorshVecLength = u32;
 const BORSH_VEC_PADDING_BYTES: usize = 4;
 const BORSH_VEC_SIZE_BYTES: usize = 4;
+const DEFAULT_MANGO_ACCOUNT_VERSION: u8 = 1;
 
 #[derive(
     Debug,
@@ -96,8 +97,7 @@ pub struct MangoAccount {
     pub account_num: u8,
     pub bump: u8,
 
-    // pub info: [u8; INFO_LEN], // TODO: Info could be in a separate PDA?
-    pub reserved: [u8; 4],
+    pub padding: [u8; 4],
 
     // Cumulative (deposits - withdraws)
     // using USD prices at the time of the deposit/withdraw
@@ -107,7 +107,11 @@ pub struct MangoAccount {
     // TODO: unimplemented
     pub net_settled: f32,
 
+    pub reserved: [u8; 256],
+
     // dynamic
+    pub header_version: u8,
+    pub padding0: [u8; 7],
     // note: padding is required for TokenPosition, etc. to be aligned
     pub padding1: u32,
     // Maps token_index -> deposit/borrow account for each token
@@ -134,9 +138,12 @@ impl Default for MangoAccount {
             is_bankrupt: 0,
             account_num: 0,
             bump: 0,
-            reserved: Default::default(),
+            padding: Default::default(),
             net_deposits: 0.0,
             net_settled: 0.0,
+            reserved: [0; 256],
+            header_version: DEFAULT_MANGO_ACCOUNT_VERSION,
+            padding0: Default::default(),
             padding1: Default::default(),
             tokens: vec![TokenPosition::default(); 3],
             padding2: Default::default(),
@@ -158,7 +165,8 @@ impl MangoAccount {
     }
 
     pub fn dynamic_token_vec_offset() -> usize {
-        BORSH_VEC_PADDING_BYTES
+        8 // header version + padding
+            + BORSH_VEC_PADDING_BYTES
     }
 
     pub fn dynamic_serum3_vec_offset(token_count: u8) -> usize {
@@ -217,11 +225,12 @@ pub struct MangoAccountFixed {
     is_bankrupt: u8,
     pub account_num: u8,
     pub bump: u8,
-    pub reserved: [u8; 4],
+    pub padding: [u8; 4],
     pub net_deposits: f32,
     pub net_settled: f32,
+    pub reserved: [u8; 256],
 }
-const_assert_eq!(size_of::<MangoAccountFixed>(), 32 * 4 + 4 + 4 + 2 * 4);
+const_assert_eq!(size_of::<MangoAccountFixed>(), 32 * 4 + 4 + 4 + 2 * 4 + 256);
 const_assert_eq!(size_of::<MangoAccountFixed>() % 8, 0);
 
 impl MangoAccountFixed {
@@ -267,43 +276,52 @@ pub struct MangoAccountDynamicHeader {
 
 impl DynamicHeader for MangoAccountDynamicHeader {
     fn from_bytes(data: &[u8]) -> Result<Self> {
-        let token_count = u8::try_from(BorshVecLength::from_le_bytes(*array_ref![
-            data,
-            MangoAccount::dynamic_token_vec_offset(),
-            BORSH_VEC_SIZE_BYTES
-        ]))
-        .unwrap();
+        let header_version = u8::from_le_bytes(*array_ref![data, 0, size_of::<u8>()]);
 
-        let serum3_count = u8::try_from(BorshVecLength::from_le_bytes(*array_ref![
-            data,
-            MangoAccount::dynamic_serum3_vec_offset(token_count),
-            BORSH_VEC_SIZE_BYTES
-        ]))
-        .unwrap();
+        match header_version {
+            1 => {
+                let token_count = u8::try_from(BorshVecLength::from_le_bytes(*array_ref![
+                    data,
+                    MangoAccount::dynamic_token_vec_offset(),
+                    BORSH_VEC_SIZE_BYTES
+                ]))
+                .unwrap();
 
-        let perp_count = u8::try_from(BorshVecLength::from_le_bytes(*array_ref![
-            data,
-            MangoAccount::dynamic_perp_vec_offset(token_count, serum3_count),
-            BORSH_VEC_SIZE_BYTES
-        ]))
-        .unwrap();
+                let serum3_count = u8::try_from(BorshVecLength::from_le_bytes(*array_ref![
+                    data,
+                    MangoAccount::dynamic_serum3_vec_offset(token_count),
+                    BORSH_VEC_SIZE_BYTES
+                ]))
+                .unwrap();
 
-        let perp_oo_count = u8::try_from(BorshVecLength::from_le_bytes(*array_ref![
-            data,
-            MangoAccount::dynamic_perp_oo_vec_offset(token_count, serum3_count, perp_count),
-            BORSH_VEC_SIZE_BYTES
-        ]))
-        .unwrap();
+                let perp_count = u8::try_from(BorshVecLength::from_le_bytes(*array_ref![
+                    data,
+                    MangoAccount::dynamic_perp_vec_offset(token_count, serum3_count),
+                    BORSH_VEC_SIZE_BYTES
+                ]))
+                .unwrap();
 
-        Ok(Self {
-            token_count,
-            serum3_count,
-            perp_count,
-            perp_oo_count,
-        })
+                let perp_oo_count = u8::try_from(BorshVecLength::from_le_bytes(*array_ref![
+                    data,
+                    MangoAccount::dynamic_perp_oo_vec_offset(token_count, serum3_count, perp_count),
+                    BORSH_VEC_SIZE_BYTES
+                ]))
+                .unwrap();
+
+                Ok(Self {
+                    token_count,
+                    serum3_count,
+                    perp_count,
+                    perp_oo_count,
+                })
+            }
+            _ => err!(MangoError::NotImplementedError).context("unexpected header version number"),
+        }
     }
 
-    fn initialize(_data: &mut [u8]) -> Result<()> {
+    fn initialize(data: &mut [u8]) -> Result<()> {
+        let dst: &mut [u8] = &mut data[0..1];
+        dst.copy_from_slice(&DEFAULT_MANGO_ACCOUNT_VERSION.to_le_bytes());
         Ok(())
     }
 }
@@ -620,7 +638,8 @@ impl<
                     indexed_position: I80F48::ZERO,
                     token_index,
                     in_use_count: 0,
-                    reserved: Default::default(),
+                    padding: Default::default(),
+                    reserved: [0; 40],
                 };
             }
             Ok((v, raw_index, bank_index))
diff --git a/programs/mango-v4/src/state/mango_account_components.rs b/programs/mango-v4/src/state/mango_account_components.rs
index aa06ee7e7..a53bc6251 100644
--- a/programs/mango-v4/src/state/mango_account_components.rs
+++ b/programs/mango-v4/src/state/mango_account_components.rs
@@ -26,13 +26,15 @@ pub struct TokenPosition {
     /// incremented when a market requires this position to stay alive
     pub in_use_count: u8,
 
-    pub reserved: [u8; 5],
+    pub padding: [u8; 5],
+
+    pub reserved: [u8; 40],
 }
 
 unsafe impl bytemuck::Pod for TokenPosition {}
 unsafe impl bytemuck::Zeroable for TokenPosition {}
 
-const_assert_eq!(size_of::<TokenPosition>(), 24);
+const_assert_eq!(size_of::<TokenPosition>(), 24 + 40);
 const_assert_eq!(size_of::<TokenPosition>() % 8, 0);
 
 impl Default for TokenPosition {
@@ -41,7 +43,8 @@ impl Default for TokenPosition {
             indexed_position: I80F48::ZERO,
             token_index: TokenIndex::MAX,
             in_use_count: 0,
-            reserved: Default::default(),
+            padding: Default::default(),
+            reserved: [0; 40],
         }
     }
 }
@@ -98,9 +101,11 @@ pub struct Serum3Orders {
     pub base_token_index: TokenIndex,
     pub quote_token_index: TokenIndex,
 
-    pub reserved: [u8; 2],
+    pub padding: [u8; 2],
+
+    pub reserved: [u8; 64],
 }
-const_assert_eq!(size_of::<Serum3Orders>(), 32 + 8 * 2 + 2 * 3 + 2); // 56
+const_assert_eq!(size_of::<Serum3Orders>(), 32 + 8 * 2 + 2 * 3 + 2 + 64);
 const_assert_eq!(size_of::<Serum3Orders>() % 8, 0);
 
 unsafe impl bytemuck::Pod for Serum3Orders {}
@@ -123,7 +128,8 @@ impl Default for Serum3Orders {
             market_index: Serum3MarketIndex::MAX,
             base_token_index: TokenIndex::MAX,
             quote_token_index: TokenIndex::MAX,
-            reserved: Default::default(),
+            reserved: [0; 64],
+            padding: Default::default(),
             previous_native_coin_reserved: 0,
             previous_native_pc_reserved: 0,
         }
@@ -134,7 +140,7 @@ impl Default for Serum3Orders {
 #[derive(AnchorSerialize, AnchorDeserialize)]
 pub struct PerpPositions {
     pub market_index: PerpMarketIndex,
-    pub reserved: [u8; 6],
+    pub padding: [u8; 6],
 
     /// Active position size, measured in base lots
     pub base_position_lots: i64,
@@ -157,6 +163,8 @@ pub struct PerpPositions {
     /// Amount that's on EventQueue waiting to be processed
     pub taker_base_lots: i64,
     pub taker_quote_lots: i64,
+
+    pub reserved: [u8; 64],
 }
 
 impl std::fmt::Debug for PerpPositions {
@@ -172,7 +180,7 @@ impl std::fmt::Debug for PerpPositions {
             .finish()
     }
 }
-const_assert_eq!(size_of::<PerpPositions>(), 8 + 8 * 5 + 3 * 16); // 96
+const_assert_eq!(size_of::<PerpPositions>(), 8 + 8 * 5 + 3 * 16 + 64);
 const_assert_eq!(size_of::<PerpPositions>() % 8, 0);
 
 unsafe impl bytemuck::Pod for PerpPositions {}
@@ -188,9 +196,10 @@ impl Default for PerpPositions {
             asks_base_lots: 0,
             taker_base_lots: 0,
             taker_quote_lots: 0,
-            reserved: Default::default(),
+            reserved: [0; 64],
             long_settled_funding: I80F48::ZERO,
             short_settled_funding: I80F48::ZERO,
+            padding: Default::default(),
         }
     }
 }
@@ -254,22 +263,24 @@ impl PerpPositions {
 #[derive(AnchorSerialize, AnchorDeserialize, Debug)]
 pub struct PerpOpenOrders {
     pub order_side: Side, // TODO: storing enums isn't POD
-    pub reserved1: [u8; 1],
+    pub padding1: [u8; 1],
     pub order_market: PerpMarketIndex,
-    pub reserved2: [u8; 4],
+    pub padding2: [u8; 4],
     pub client_order_id: u64,
     pub order_id: i128,
+    pub reserved: [u8; 64],
 }
 
 impl Default for PerpOpenOrders {
     fn default() -> Self {
         Self {
             order_side: Side::Bid,
-            reserved1: Default::default(),
+            padding1: Default::default(),
             order_market: FREE_ORDER_SLOT,
-            reserved2: Default::default(),
+            padding2: Default::default(),
             client_order_id: 0,
             order_id: 0,
+            reserved: [0; 64],
         }
     }
 }
@@ -277,7 +288,7 @@ impl Default for PerpOpenOrders {
 unsafe impl bytemuck::Pod for PerpOpenOrders {}
 unsafe impl bytemuck::Zeroable for PerpOpenOrders {}
 
-const_assert_eq!(size_of::<PerpOpenOrders>(), 1 + 1 + 2 + 4 + 8 + 16);
+const_assert_eq!(size_of::<PerpOpenOrders>(), 1 + 1 + 2 + 4 + 8 + 16 + 64);
 const_assert_eq!(size_of::<PerpOpenOrders>() % 8, 0);
 
 #[macro_export]
diff --git a/programs/mango-v4/src/state/mint_info.rs b/programs/mango-v4/src/state/mint_info.rs
index 47d7ef5e8..5c7144df7 100644
--- a/programs/mango-v4/src/state/mint_info.rs
+++ b/programs/mango-v4/src/state/mint_info.rs
@@ -21,7 +21,7 @@ pub struct MintInfo {
     // ABI: Clients rely on this being at offset 40
     pub token_index: TokenIndex,
 
-    pub padding: [u8; 6],
+    pub padding1: [u8; 6],
     pub mint: Pubkey,
     pub banks: [Pubkey; MAX_BANKS],
     pub vaults: [Pubkey; MAX_BANKS],
@@ -32,11 +32,13 @@ pub struct MintInfo {
     pub address_lookup_table_bank_index: u8,
     pub address_lookup_table_oracle_index: u8,
 
-    pub reserved: [u8; 6],
+    pub padding2: [u8; 6],
+
+    pub reserved: [u8; 256],
 }
 const_assert_eq!(
     size_of::<MintInfo>(),
-    MAX_BANKS * 2 * 32 + 4 * 32 + 2 + 6 + 2 + 6
+    MAX_BANKS * 2 * 32 + 4 * 32 + 2 + 6 + 2 + 6 + 256
 );
 const_assert_eq!(size_of::<MintInfo>() % 8, 0);
 
diff --git a/programs/mango-v4/src/state/oracle.rs b/programs/mango-v4/src/state/oracle.rs
index 94559f9a2..9fc09d290 100644
--- a/programs/mango-v4/src/state/oracle.rs
+++ b/programs/mango-v4/src/state/oracle.rs
@@ -78,9 +78,9 @@ pub struct StubOracle {
     pub mint: Pubkey,
     pub price: I80F48,
     pub last_updated: i64,
-    pub reserved: [u8; 8],
+    pub reserved: [u8; 128],
 }
-const_assert_eq!(size_of::<StubOracle>(), 32 + 32 + 16 + 8 + 8);
+const_assert_eq!(size_of::<StubOracle>(), 32 + 32 + 16 + 8 + 128);
 const_assert_eq!(size_of::<StubOracle>() % 8, 0);
 
 pub fn determine_oracle_type(acc_info: &impl KeyedAccountReader) -> Result<OracleType> {
diff --git a/programs/mango-v4/src/state/orderbook/bookside.rs b/programs/mango-v4/src/state/orderbook/bookside.rs
index fc41d5a19..5bb941f38 100644
--- a/programs/mango-v4/src/state/orderbook/bookside.rs
+++ b/programs/mango-v4/src/state/orderbook/bookside.rs
@@ -45,10 +45,11 @@ pub struct BookSide {
     pub root_node: NodeHandle,
     pub leaf_count: u32,
     pub nodes: [AnyNode; MAX_BOOK_NODES],
+    pub reserved: [u8; 256],
 }
 const_assert_eq!(
     std::mem::size_of::<BookSide>(),
-    1 + 3 + 4 * 2 + 4 + 4 + 4 + 88 * 1024
+    1 + 3 + 4 * 2 + 4 + 4 + 4 + 96 * 1024 + 256 // 98584
 );
 const_assert_eq!(std::mem::size_of::<BookSide>() % 8, 0);
 
@@ -262,7 +263,7 @@ impl BookSide {
                 NodeTag::FreeNode.into()
             },
             next: self.free_list_head,
-            reserve: [0; 80],
+            reserved: [0; 88],
         });
 
         self.free_list_len += 1;
@@ -458,6 +459,7 @@ mod tests {
             root_node: 0,
             leaf_count: 0,
             nodes: [AnyNode::zeroed(); MAX_BOOK_NODES],
+            reserved: [0; 256],
         }
     }
 
diff --git a/programs/mango-v4/src/state/orderbook/mod.rs b/programs/mango-v4/src/state/orderbook/mod.rs
index f34c45a4c..a5df865b8 100644
--- a/programs/mango-v4/src/state/orderbook/mod.rs
+++ b/programs/mango-v4/src/state/orderbook/mod.rs
@@ -32,6 +32,7 @@ mod tests {
             root_node: 0,
             leaf_count: 0,
             nodes: [AnyNode::zeroed(); MAX_BOOK_NODES],
+            reserved: [0; 256],
         }
     }
 
diff --git a/programs/mango-v4/src/state/orderbook/nodes.rs b/programs/mango-v4/src/state/orderbook/nodes.rs
index 7ffc18b52..7d86c244c 100644
--- a/programs/mango-v4/src/state/orderbook/nodes.rs
+++ b/programs/mango-v4/src/state/orderbook/nodes.rs
@@ -9,7 +9,7 @@ use static_assertions::const_assert_eq;
 use super::order_type::OrderType;
 
 pub type NodeHandle = u32;
-const NODE_SIZE: usize = 88;
+const NODE_SIZE: usize = 96;
 
 #[derive(IntoPrimitive, TryFromPrimitive)]
 #[repr(u32)]
@@ -46,7 +46,7 @@ pub struct InnerNode {
     /// iterate through the whole bookside.
     pub child_earliest_expiry: [u64; 2],
 
-    pub reserve: [u8; NODE_SIZE - 48],
+    pub reserved: [u8; NODE_SIZE - 48],
 }
 
 impl InnerNode {
@@ -57,7 +57,7 @@ impl InnerNode {
             key,
             children: [0; 2],
             child_earliest_expiry: [u64::MAX; 2],
-            reserve: [0; NODE_SIZE - 48],
+            reserved: [0; NODE_SIZE - 48],
         }
     }
 
@@ -98,7 +98,7 @@ pub struct LeafNode {
     // The time the order was placed
     pub timestamp: u64,
 
-    pub reserve: [u8; NODE_SIZE - 81],
+    pub reserved: [u8; NODE_SIZE - 81],
 }
 
 #[inline(always)]
@@ -128,7 +128,7 @@ impl LeafNode {
             quantity,
             client_order_id,
             timestamp,
-            reserve: [0; NODE_SIZE - 81],
+            reserved: [0; NODE_SIZE - 81],
         }
     }
 
@@ -158,14 +158,14 @@ impl LeafNode {
 pub struct FreeNode {
     pub(crate) tag: u32,
     pub(crate) next: NodeHandle,
-    pub(crate) reserve: [u8; NODE_SIZE - 8],
+    pub(crate) reserved: [u8; NODE_SIZE - 8],
 }
 
 #[zero_copy]
 #[derive(Pod)]
 pub struct AnyNode {
     pub tag: u32,
-    pub data: [u8; 84], // note: anchor can't parse the struct for IDL when it includes non numbers, NODE_SIZE == 88, 84 == 88 - 4
+    pub data: [u8; 92], // note: anchor can't parse the struct for IDL when it includes non numbers, NODE_SIZE == 96, 92 == 96 - 4
 }
 
 const_assert_eq!(size_of::<AnyNode>(), NODE_SIZE);
diff --git a/programs/mango-v4/src/state/orderbook/queue.rs b/programs/mango-v4/src/state/orderbook/queue.rs
index 328283479..f25e34435 100644
--- a/programs/mango-v4/src/state/orderbook/queue.rs
+++ b/programs/mango-v4/src/state/orderbook/queue.rs
@@ -8,7 +8,7 @@ use std::mem::size_of;
 
 use super::Side;
 
-pub const MAX_NUM_EVENTS: u32 = 512;
+pub const MAX_NUM_EVENTS: u32 = 488;
 
 pub trait QueueHeader: bytemuck::Pod {
     type Item: bytemuck::Pod + Copy;
@@ -153,15 +153,15 @@ impl QueueHeader for EventQueueHeader {
     }
 }
 
-const_assert_eq!(std::mem::size_of::<EventQueue>(), 4 * 2 + 8 + 512 * 200);
+const_assert_eq!(std::mem::size_of::<EventQueue>(), 4 * 2 + 8 + 488 * 208);
 const_assert_eq!(std::mem::size_of::<EventQueue>() % 8, 0);
 
-const EVENT_SIZE: usize = 200;
+const EVENT_SIZE: usize = 208;
 #[zero_copy]
 #[derive(Debug, Pod)]
 pub struct AnyEvent {
     pub event_type: u8,
-    pub padding: [u8; 199], // note: anchor can't parse the struct for IDL when it includes non numbers, EVENT_SIZE == 200, 199 == 200 - 1
+    pub padding: [u8; 207], // note: anchor can't parse the struct for IDL when it includes non numbers, EVENT_SIZE == 208, 207 == 208 - 1
 }
 
 const_assert_eq!(size_of::<AnyEvent>(), EVENT_SIZE);
@@ -201,7 +201,7 @@ pub struct FillEvent {
 
     pub price: i64,
     pub quantity: i64, // number of quote lots
-    pub reserved: [u8; 8],
+    pub reserved: [u8; 16],
 }
 const_assert_eq!(size_of::<FillEvent>(), EVENT_SIZE);
 
@@ -246,7 +246,7 @@ impl FillEvent {
             taker_fee,
             price,
             quantity,
-            reserved: Default::default(),
+            reserved: [0; 16],
         }
     }
 
diff --git a/programs/mango-v4/src/state/perp_market.rs b/programs/mango-v4/src/state/perp_market.rs
index ff293ec1f..dc20cd4a6 100644
--- a/programs/mango-v4/src/state/perp_market.rs
+++ b/programs/mango-v4/src/state/perp_market.rs
@@ -26,7 +26,7 @@ pub struct PerpMarket {
     /// Lookup indices
     pub perp_market_index: PerpMarketIndex,
 
-    pub padding: [u8; 4],
+    pub padding1: [u8; 4],
 
     pub name: [u8; 16],
 
@@ -86,12 +86,14 @@ pub struct PerpMarket {
 
     pub base_token_decimals: u8,
 
-    pub reserved: [u8; 6],
+    pub padding2: [u8; 6],
+
+    pub reserved: [u8; 128],
 }
 
 const_assert_eq!(
     size_of::<PerpMarket>(),
-    32 + 2 + 2 + 4 + 16 + 32 + 16 + 32 * 3 + 8 * 2 + 16 * 11 + 8 * 2 + 8 * 2 + 16 + 2 + 6
+    32 + 2 + 2 + 4 + 16 + 32 + 16 + 32 * 3 + 8 * 2 + 16 * 11 + 8 * 2 + 8 * 2 + 16 + 2 + 6 + 128
 );
 const_assert_eq!(size_of::<PerpMarket>() % 8, 0);
 
diff --git a/programs/mango-v4/src/state/serum3_market.rs b/programs/mango-v4/src/state/serum3_market.rs
index dd861f01d..350bd1d1b 100644
--- a/programs/mango-v4/src/state/serum3_market.rs
+++ b/programs/mango-v4/src/state/serum3_market.rs
@@ -15,7 +15,7 @@ pub struct Serum3Market {
     pub base_token_index: TokenIndex,
     // ABI: Clients rely on this being at offset 42
     pub quote_token_index: TokenIndex,
-    pub padding: [u8; 4],
+    pub padding1: [u8; 4],
     pub name: [u8; 16],
     pub serum_program: Pubkey,
     pub serum_market_external: Pubkey,
@@ -23,11 +23,14 @@ pub struct Serum3Market {
     pub market_index: Serum3MarketIndex,
 
     pub bump: u8,
-    pub reserved: [u8; 5],
+
+    pub padding2: [u8; 5],
+
+    pub reserved: [u8; 128],
 }
 const_assert_eq!(
     size_of::<Serum3Market>(),
-    32 + 2 + 2 + 4 + 16 + 2 * 32 + 2 + 1 + 5
+    32 + 2 + 2 + 4 + 16 + 2 * 32 + 2 + 1 + 5 + 128
 );
 const_assert_eq!(size_of::<Serum3Market>() % 8, 0);