diff --git a/Cargo.toml b/Cargo.toml
index abf0292..c062ab6 100755
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "solana-streamer-sdk"
-version = "1.5.0"
+version = "1.5.1"
 edition = "2021"
 authors = ["William <byteblock6@gmail.com>", "sgxiang <sgxiang@gmail.com>", "wei <1415121722@qq.com>"]
 repository = "https://github.com/0xfnzero/solana-streamer"
@@ -15,13 +15,13 @@ crate-type = ["cdylib", "rlib"]
 [features]
 default = ["sdk-parse-borsh"]
 sdk-parse-borsh = ["sol-parser-sdk/parse-borsh"]
-# If both parser backend features are enabled, sol-parser-sdk 0.5.0+ uses zero-copy.
+# If both parser backend features are enabled, sol-parser-sdk 0.5.1+ uses zero-copy.
 sdk-parse-zero-copy = ["sol-parser-sdk/parse-zero-copy"]
 sdk-perf-stats = ["sol-parser-sdk/perf-stats"]
 sdk-ultra-perf = ["sol-parser-sdk/ultra-perf"]
 
 [dependencies]
-sol-parser-sdk = { version = "0.5.0", default-features = false }
+sol-parser-sdk = { version = "0.5.1", default-features = false }
 solana-sdk = "3.0.0"
 solana-client = "3.1.12"
 solana-transaction-status = "3.1.12"
diff --git a/README.md b/README.md
index 832ae0d..5c26760 100755
--- a/README.md
+++ b/README.md
@@ -70,7 +70,7 @@
 - **Real-time Event Streaming**: Subscribe to live trading events from multiple Solana DEX protocols
 - **SDK-backed Parser Core**: Transaction, RPC, account, and ShredStream parsing are backed by `sol-parser-sdk`
 - **Yellowstone gRPC Support**: High-performance event subscription using Yellowstone gRPC
-- **ShredStream Support**: Alternative event streaming using ShredStream protocol
+- **ShredStream Support**: Alternative event streaming using ShredStream protocol; ALT-loaded accounts are parsed best-effort with default account placeholders
 - **Unified Event Interface**: Consistent event handling across all supported protocols
 
 ### Multi-Protocol Support
@@ -123,30 +123,34 @@ Add the dependency to your `Cargo.toml`:
 
 ```toml
 # Add to your Cargo.toml
-solana-streamer-sdk = { path = "./solana-streamer", version = "1.5.0" }
+solana-streamer-sdk = { path = "./solana-streamer", version = "1.5.1" }
 ```
 
 ### Use crates.io
 
 ```toml
 # Add to your Cargo.toml
-solana-streamer-sdk = "1.5.0"
+solana-streamer-sdk = "1.5.1"
 ```
 
 Parser backend features:
 
 ```toml
 # Default: sol-parser-sdk parse-borsh backend
-solana-streamer-sdk = "1.5.0"
+solana-streamer-sdk = "1.5.1"
 
 # Zero-copy parser backend for latency-sensitive bots
-solana-streamer-sdk = { version = "1.5.0", default-features = false, features = ["sdk-parse-zero-copy"] }
+solana-streamer-sdk = { version = "1.5.1", default-features = false, features = ["sdk-parse-zero-copy"] }
 ```
 
-If both `sdk-parse-borsh` and `sdk-parse-zero-copy` are enabled, `sol-parser-sdk 0.5.0+` uses the zero-copy backend.
+If both `sdk-parse-borsh` and `sdk-parse-zero-copy` are enabled, `sol-parser-sdk 0.5.1+` uses the zero-copy backend.
 
 ## 🔄 Migration Guide
 
+### Upgrading to v1.5.1
+
+Version 1.5.1 uses `sol-parser-sdk 0.5.1` from crates.io. It improves ShredStream ALT handling by parsing outer instructions best-effort with default placeholders for ALT-loaded accounts, adds dropped-event queue observability, and keeps CPI/inner-only events documented as a ShredStream limitation.
+
 ### Upgrading to v1.5.0
 
 Version 1.5.0 uses `sol-parser-sdk 0.5.0`, wires Raydium CLMM account parsing through the SDK bridge, and reduces ordered-buffer allocation/move overhead in low-latency delivery paths. `sol-parser-sdk 0.4.19` and `solana-streamer-sdk 1.4.14` were superseded because adding public parser event variants belongs in the 0.5 line.
diff --git a/README_CN.md b/README_CN.md
index 45a56d2..4b6cad0 100644
--- a/README_CN.md
+++ b/README_CN.md
@@ -69,7 +69,7 @@
 - **实时事件流**: 订阅多个 Solana DEX 协议的实时交易事件
 - **SDK 底层解析核心**: 交易、RPC、账户和 ShredStream 解析都优先复用 `sol-parser-sdk`
 - **Yellowstone gRPC 支持**: 使用 Yellowstone gRPC 进行高性能事件订阅
-- **ShredStream 支持**: 使用 ShredStream 协议进行替代事件流传输
+- **ShredStream 支持**: 使用 ShredStream 协议进行替代事件流传输；ALT-loaded 账户会以默认账户占位并尽量解析外层事件
 - **统一事件接口**: 在所有支持的协议中保持一致的事件处理
 
 ### 多协议支持
@@ -122,30 +122,34 @@ git clone https://github.com/0xfnzero/solana-streamer
 
 ```toml
 # 添加到您的 Cargo.toml
-solana-streamer-sdk = { path = "./solana-streamer", version = "1.5.0" }
+solana-streamer-sdk = { path = "./solana-streamer", version = "1.5.1" }
 ```
 
 ### 使用 crates.io
 
 ```toml
 # 添加到您的 Cargo.toml
-solana-streamer-sdk = "1.5.0"
+solana-streamer-sdk = "1.5.1"
 ```
 
 解析后端 feature：
 
 ```toml
 # 默认：sol-parser-sdk parse-borsh 后端
-solana-streamer-sdk = "1.5.0"
+solana-streamer-sdk = "1.5.1"
 
 # 面向低延迟 Bot 的 zero-copy 解析后端
-solana-streamer-sdk = { version = "1.5.0", default-features = false, features = ["sdk-parse-zero-copy"] }
+solana-streamer-sdk = { version = "1.5.1", default-features = false, features = ["sdk-parse-zero-copy"] }
 ```
 
-如果同时启用 `sdk-parse-borsh` 和 `sdk-parse-zero-copy`，`sol-parser-sdk 0.5.0+` 会优先使用 zero-copy 后端。
+如果同时启用 `sdk-parse-borsh` 和 `sdk-parse-zero-copy`，`sol-parser-sdk 0.5.1+` 会优先使用 zero-copy 后端。
 
 ## 🔄 迁移指南
 
+### 升级到 v1.5.1
+
+v1.5.1 使用 crates.io 上的 `sol-parser-sdk 0.5.1`。该版本改进 ShredStream 的 ALT 处理：ALT-loaded 账户会以默认账户占位，外层指令按 data/discriminator 尽量解析；同时增加队列满时的 dropped event 可观测性，并明确 CPI/inner-only 事件仍是 ShredStream 的固有限制。
+
 ### 升级到 v1.5.0
 
 v1.5.0 使用 `sol-parser-sdk 0.5.0`，打通 Raydium CLMM 账户解析的 SDK bridge，并降低有序缓冲低延迟投递路径中的分配和搬移开销。`sol-parser-sdk 0.4.19` 和 `solana-streamer-sdk 1.4.14` 已由 v1.5.0 取代，因为新增公开 parser event variant 应放到 0.5 版本线。
diff --git a/docs/SHREDSTREAM_LIMITATIONS.md b/docs/SHREDSTREAM_LIMITATIONS.md
index 35bfef0..91137c3 100644
--- a/docs/SHREDSTREAM_LIMITATIONS.md
+++ b/docs/SHREDSTREAM_LIMITATIONS.md
@@ -23,8 +23,9 @@ ShredStream 路径仍为下面的原始交易解析限制，不使用上述日
 
 ### 2.1 使用 Address Lookup Tables (ALT) 的交易
 
-- **现象**：指令中的账户索引指向「static + loaded」的完整列表，shred 只传入 static，越界索引会被填成 `Pubkey::default()`（11111...）。
-- **影响协议/指令**：所有依赖「按索引取账户」的指令，在交易使用 ALT 时都可能出现错误或默认账户。
+- **现象**：指令中的账户索引指向「static + loaded」的完整列表，shred 只传入 static。当前 ShredStream 路径会尽量解析外层指令；若某个指令账户来自 ALT-loaded keys，会以 `Pubkey::default()`（11111...）占位。
+- **影响协议/指令**：所有依赖「按索引取账户」的指令，在交易使用 ALT 时都可能出现错误或默认账户；能靠指令 data / discriminator 识别的事件会 best-effort 产出。
+- **program id 也来自 ALT 时**：无法从 shred 恢复真实程序 ID，会按启用的协议/filter 进行 discriminator-only best-effort 解析。若不同协议 discriminator 碰撞，建议使用窄 filter 降低误判或多候选输出风险。
 - **典型表现**：
   - **PumpFun**：Create / CreateV2 的 token_program、global、event_authority 等为 11111...；Buy/Sell 的 creator_vault、token_program 等可能错误。
   - **PumpSwap / Bonk / Raydium / Meteora**：依赖高索引账户的指令同样可能得到错误或 default 账户。
@@ -58,7 +59,7 @@ ShredStream 路径仍为下面的原始交易解析限制，不使用上述日
 ## 3. 使用建议
 
 - 需要**完整、正确**的账户与 log 字段（reserves、timestamp、amounts、swap_data 等）时，使用 **gRPC 订阅**。
-- Shredstream 更适合：对延迟更敏感、可接受「仅指令层 + 部分字段缺失/默认」的场景，或确认交易**未使用 ALT** 时的账户解析。
+- Shredstream 更适合：对延迟更敏感、可接受「仅指令层 + 部分字段缺失/默认」的场景；使用 ALT 的交易会 best-effort 解析，但 ALT-loaded 账户字段可能为 default。
 
 ## 4. 各事件 Shred 路径字段完整性