diff --git a/Cargo.lock b/Cargo.lock
index 005166384..e5ff3ad28 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -155,6 +155,12 @@ dependencies = [
  "arbitrary",
 ]
 
+[[package]]
+name = "archery"
+version = "1.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "33ca55ee147b1926dbea904f50fe4902494e97bc742205abbbf10c709e43815f"
+
 [[package]]
 name = "arrayvec"
 version = "0.7.6"
@@ -298,6 +304,12 @@ version = "0.6.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "175812e0be2bccb6abe50bb8d566126198344f707e304f45c648fd8f2cc0365e"
 
+[[package]]
+name = "bytemuck"
+version = "1.25.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "95832e849adfb21180ccb6826a99da14e5d266ae5c2e668e1602cf234f153797"
+
 [[package]]
 name = "byteorder"
 version = "1.5.0"
@@ -1294,7 +1306,7 @@ checksum = "d0acd33ff0285af998aaf9b57342af478078f53492322fafc47450e09397e0e9"
 dependencies = [
  "bitmaps 2.1.0",
  "rand_core 0.6.4",
- "rand_xoshiro",
+ "rand_xoshiro 0.6.0",
  "serde",
  "sized-chunks",
  "typenum",
@@ -1308,10 +1320,26 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bc3be8d8cd36f33a46b1849f31f837c44d9fa87223baee3b4bd96b8f11df81eb"
 dependencies = [
  "bitmaps 3.2.1",
- "imbl-sized-chunks",
+ "imbl-sized-chunks 0.1.3",
  "rand_core 0.6.4",
- "rand_xoshiro",
+ "rand_xoshiro 0.6.0",
+ "version_check",
+]
+
+[[package]]
+name = "imbl"
+version = "7.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "46bad832b9b463ed9398b8506488cc2e3b897a9d44f13af115f382aac71f4fec"
+dependencies = [
+ "archery",
+ "equivalent",
+ "imbl-sized-chunks 0.2.0",
+ "rand_core 0.9.3",
+ "rand_xoshiro 0.7.0",
+ "serde_core",
  "version_check",
+ "wide",
 ]
 
 [[package]]
@@ -1323,6 +1351,12 @@ dependencies = [
  "bitmaps 3.2.1",
 ]
 
+[[package]]
+name = "imbl-sized-chunks"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2a0813be332553f857953298749fa19549e8b61b80589757c29b4e2a804fa9c6"
+
 [[package]]
 name = "indexmap"
 version = "1.9.3"
@@ -1732,7 +1766,7 @@ dependencies = [
  "enum_dispatch",
  "generic-btree",
  "getrandom 0.2.16",
- "im",
+ "imbl 7.0.2",
  "itertools 0.12.1",
  "js-sys",
  "leb128",
@@ -1863,7 +1897,7 @@ checksum = "3f3d053a135388e6b1df14e8af1212af5064746e9b87a06a345a7a779ee9695a"
 
 [[package]]
 name = "loro-wasm"
-version = "1.16.2"
+version = "1.16.3"
 dependencies = [
  "js-sys",
  "loro-common 1.16.0",
@@ -1894,7 +1928,7 @@ name = "loro_fractional_index"
 version = "0.16.12"
 source = "git+https://github.com/loro-dev/loro.git?tag=loro-crdt%401.0.0-alpha.4#9bfe97bce4912c6dc8439817497d18423a0e8cb7"
 dependencies = [
- "imbl",
+ "imbl 3.0.0",
  "once_cell",
  "rand 0.8.5",
  "serde",
@@ -2499,6 +2533,15 @@ dependencies = [
  "rand_core 0.6.4",
 ]
 
+[[package]]
+name = "rand_xoshiro"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f703f4665700daf5512dcca5f43afa6af89f09db47fb56be587f80636bda2d41"
+dependencies = [
+ "rand_core 0.9.3",
+]
+
 [[package]]
 name = "rayon"
 version = "1.11.0"
@@ -2626,6 +2669,15 @@ version = "1.0.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "28d3b2b1366ec20994f1fd18c3c594f05c5dd4bc44d8bb0c1c632c8d6829481f"
 
+[[package]]
+name = "safe_arch"
+version = "0.7.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "96b02de82ddbe1b636e6170c21be622223aea188ef2e139be0a5b219ec215323"
+dependencies = [
+ "bytemuck",
+]
+
 [[package]]
 name = "same-file"
 version = "1.0.6"
@@ -3407,6 +3459,16 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "wide"
+version = "0.7.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ce5da8ecb62bcd8ec8b7ea19f69a51275e91299be594ea5cc6ef7819e16cd03"
+dependencies = [
+ "bytemuck",
+ "safe_arch",
+]
+
 [[package]]
 name = "winapi"
 version = "0.3.9"
diff --git a/crates/loro-internal/Cargo.toml b/crates/loro-internal/Cargo.toml
index ca6bfd102..20dc460b7 100644
--- a/crates/loro-internal/Cargo.toml
+++ b/crates/loro-internal/Cargo.toml
@@ -37,7 +37,7 @@ once_cell = { workspace = true }
 arbitrary = { version = "1", optional = true }
 postcard = { version = "1", default-features = false, features = ["use-std"] }
 append-only-bytes = { version = "0.1.12", features = ["u32_range"] }
-im = { version = "15.1.0", features = ["serde"] }
+imbl = { version = "7.0.2", features = ["serde"] }
 tabled = { version = "0.10.0", optional = true }
 wasm-bindgen = { version = "=0.2.100", optional = true }
 js-sys = { version = "0.3.60", optional = true }
diff --git a/crates/loro-internal/src/dag/test.rs b/crates/loro-internal/src/dag/test.rs
index 9519281ff..31336a2d7 100644
--- a/crates/loro-internal/src/dag/test.rs
+++ b/crates/loro-internal/src/dag/test.rs
@@ -1,6 +1,6 @@
 #![allow(unused)]
 use arbitrary::Arbitrary;
-use im::HashSet;
+use imbl::HashSet;
 use loro_common::HasCounter;
 use std::{cmp::Ordering, sync::Arc};
 
diff --git a/crates/loro-internal/src/version.rs b/crates/loro-internal/src/version.rs
index 3efbe1498..b1d2bf301 100644
--- a/crates/loro-internal/src/version.rs
+++ b/crates/loro-internal/src/version.rs
@@ -160,7 +160,14 @@ impl VersionRange {
 /// can be created from cloning and modifying other similar version vectors.
 #[repr(transparent)]
 #[derive(Debug, Clone, Default, Serialize, Deserialize)]
-pub struct ImVersionVector(im::HashMap<PeerID, Counter, rustc_hash::FxBuildHasher>);
+pub struct ImVersionVector(
+    imbl::GenericHashMap<
+        PeerID,
+        Counter,
+        rustc_hash::FxBuildHasher,
+        imbl::shared_ptr::DefaultSharedPtr,
+    >,
+);
 
 #[inline]
 fn normalize_vv_counter(counter: Counter) -> Counter {
@@ -197,7 +204,9 @@ impl ImVersionVector {
         self.0.is_empty()
     }
 
-    pub fn iter(&self) -> im::hashmap::Iter<'_, PeerID, Counter> {
+    pub fn iter(
+        &self,
+    ) -> imbl::hashmap::Iter<'_, PeerID, Counter, imbl::shared_ptr::DefaultSharedPtr> {
         self.0.iter()
     }