diff --git a/src/types/block.zig b/src/types/block.zig
index 51993f3..f031384 100644
--- a/src/types/block.zig
+++ b/src/types/block.zig
@@ -45,6 +45,28 @@ pub const BlockHeader = struct {
         allocator.free(self.extra_data);
         self.* = undefined;
     }
+
+    // defines a custom encoder so that fields that were added later on in the chain history
+    // are not included in the RLP when hashing.
+    pub fn encodeToRLP(self: *const BlockHeader, allocator: Allocator, list: *std.ArrayList(u8)) !void {
+        if (self.parent_beacon_root != null) {
+            return rlp.serialize(BlockHeader, allocator, self.*, list);
+        }
+        if (self.blob_gas_used != null) {
+            const tmp = .{ self.parent_hash, self.uncle_hash, self.fee_recipient, self.state_root, self.transactions_root, self.receipts_root, self.logs_bloom, self.difficulty, self.block_number, self.gas_limit, self.gas_used, self.timestamp, self.extra_data, self.prev_randao, self.nonce, self.base_fee_per_gas.?, self.withdrawals_root.?, self.blob_gas_used.?, self.excess_blob_gas.? };
+            return rlp.serialize(@TypeOf(tmp), allocator, tmp, list);
+        }
+        if (self.withdrawals_root != null) {
+            const tmp = .{ self.parent_hash, self.uncle_hash, self.fee_recipient, self.state_root, self.transactions_root, self.receipts_root, self.logs_bloom, self.difficulty, self.block_number, self.gas_limit, self.gas_used, self.timestamp, self.extra_data, self.prev_randao, self.nonce, self.base_fee_per_gas.?, self.withdrawals_root.? };
+            return rlp.serialize(@TypeOf(tmp), allocator, tmp, list);
+        }
+        if (self.base_fee_per_gas != null) {
+            const tmp = .{ self.parent_hash, self.uncle_hash, self.fee_recipient, self.state_root, self.transactions_root, self.receipts_root, self.logs_bloom, self.difficulty, self.block_number, self.gas_limit, self.gas_used, self.timestamp, self.extra_data, self.prev_randao, self.nonce, self.base_fee_per_gas.? };
+            return rlp.serialize(@TypeOf(tmp), allocator, tmp, list);
+        }
+        const tmp = .{ self.parent_hash, self.uncle_hash, self.fee_recipient, self.state_root, self.transactions_root, self.receipts_root, self.logs_bloom, self.difficulty, self.block_number, self.gas_limit, self.gas_used, self.timestamp, self.extra_data, self.prev_randao, self.nonce };
+        return rlp.serialize(@TypeOf(tmp), allocator, tmp, list);
+    }
 };
 
 pub const Block = struct {