diff --git a/CHANGELOG.MD b/CHANGELOG.MD
index 54e68d52..c01e24b6 100644
--- a/CHANGELOG.MD
+++ b/CHANGELOG.MD
@@ -1,5 +1,11 @@
 # Changelog
 
+## 4.0.0
+* make when_created field optional for json file import by @camfairchild in https://github.com/opentensor/btwallet/pull/160
+* Fix hotkeypub by @thewhaleking in https://github.com/opentensor/btwallet/pull/161
+
+**Full Changelog**: https://github.com/opentensor/btwallet/compare/v3.1.0...v4.0.0
+
 ## 3.1.0 /2025-07-07
 
 ## What's Changed
diff --git a/Cargo.lock b/Cargo.lock
index b4a376aa..0512afde 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,6 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 4
+version = 3
 
 [[package]]
 name = "Inflector"
@@ -122,9 +122,9 @@ dependencies = [
 
 [[package]]
 name = "anstream"
-version = "0.6.18"
+version = "0.6.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8acc5369981196006228e28809f761875c0327210a891e941f4c683b3a99529b"
+checksum = "301af1932e46185686725e0fad2f8f2aa7da69dd70bf6ecc44d6b703844a3933"
 dependencies = [
  "anstyle",
  "anstyle-parse",
@@ -137,35 +137,36 @@ dependencies = [
 
 [[package]]
 name = "anstyle"
-version = "1.0.10"
+version = "1.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "55cc3b69f167a1ef2e161439aa98aed94e6028e5f9a59be9a6ffb47aef1651f9"
+checksum = "862ed96ca487e809f1c8e5a8447f6ee2cf102f846893800b20cebdf541fc6bbd"
 
 [[package]]
 name = "anstyle-parse"
-version = "0.2.6"
+version = "0.2.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3b2d16507662817a6a20a9ea92df6652ee4f94f914589377d69f3b21bc5798a9"
+checksum = "4e7644824f0aa2c7b9384579234ef10eb7efb6a0deb83f9630a49594dd9c15c2"
 dependencies = [
  "utf8parse",
 ]
 
 [[package]]
 name = "anstyle-query"
-version = "1.1.2"
+version = "1.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "79947af37f4177cfead1110013d678905c37501914fba0efea834c3fe9a8d60c"
+checksum = "6c8bdeb6047d8983be085bab0ba1472e6dc604e7041dbf6fcd5e71523014fae9"
 dependencies = [
  "windows-sys 0.59.0",
 ]
 
 [[package]]
 name = "anstyle-wincon"
-version = "3.0.6"
+version = "3.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2109dbce0e72be3ec00bed26e6a7479ca384ad226efdd66db8fa2e3a38c83125"
+checksum = "403f75924867bb1033c59fbf0797484329750cfbe3c4325cd33127941fabc882"
 dependencies = [
  "anstyle",
+ "once_cell_polyfill",
  "windows-sys 0.59.0",
 ]
 
@@ -401,7 +402,7 @@ checksum = "b048fb63fd8b5923fc5aa7b340d8e156aec7ec02f0c78fa8a6ddc2613f6f71de"
 
 [[package]]
 name = "bittensor_wallet"
-version = "3.1.0"
+version = "4.0.0"
 dependencies = [
  "ansible-vault",
  "base64 0.22.1",
@@ -424,7 +425,7 @@ dependencies = [
  "shellexpand",
  "sodiumoxide",
  "sp-core",
- "thiserror 2.0.3",
+ "thiserror 2.0.12",
 ]
 
 [[package]]
@@ -576,18 +577,18 @@ dependencies = [
 
 [[package]]
 name = "clap"
-version = "4.5.21"
+version = "4.5.41"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fb3b4b9e5a7c7514dfa52869339ee98b3156b0bfb4e8a77c4ff4babb64b1604f"
+checksum = "be92d32e80243a54711e5d7ce823c35c41c9d929dc4ab58e1276f625841aadf9"
 dependencies = [
  "clap_builder",
 ]
 
 [[package]]
 name = "clap_builder"
-version = "4.5.21"
+version = "4.5.41"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b17a95aa67cc7b5ebd32aa5370189aa0d79069ef1c64ce893bd30fb24bff20ec"
+checksum = "707eab41e9622f9139419d573eca0900137718000c517d47da73045f54331c3d"
 dependencies = [
  "anstream",
  "anstyle",
@@ -597,15 +598,15 @@ dependencies = [
 
 [[package]]
 name = "clap_lex"
-version = "0.7.3"
+version = "0.7.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "afb84c814227b90d6895e01398aee0d8033c00e7466aca416fb6a8e0eb19d8a7"
+checksum = "b94f61472cee1439c0b966b47e3aca9ae07e45d070759512cd390ea2bebc6675"
 
 [[package]]
 name = "colorchoice"
-version = "1.0.3"
+version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5b63caa9aa9397e2d9480a9b13673856c78d8ac123288526c37d7839f2a86990"
+checksum = "b05b61dc5112cbb17e4b6cd61790d9845d13888356391624cbe7e41efeac1e75"
 
 [[package]]
 name = "colored"
@@ -722,7 +723,7 @@ checksum = "f46882e17999c6cc590af592290432be3bce0428cb0d5f8b6715e4dc7b383eb3"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -754,7 +755,7 @@ checksum = "5f33878137e4dafd7fa914ad4e259e18a4e8e532b9617a2d0150262bf53abfce"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -925,7 +926,7 @@ dependencies = [
  "prettyplease",
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -1066,7 +1067,7 @@ checksum = "87750cf4b7a4c0625b1529e4c543c2182106e4dedc60a2a6455e00d212c489ac"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -1544,6 +1545,12 @@ version = "1.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
 
+[[package]]
+name = "once_cell_polyfill"
+version = "1.70.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a4895175b425cb1f87721b59f0f286c2092bd4af812243672510e1ac53e2e0ad"
+
 [[package]]
 name = "opaque-debug"
 version = "0.3.1"
@@ -1552,9 +1559,9 @@ checksum = "c08d65885ee38876c4f86fa503fb49d7b507c2b62552df7c70b2fce627e06381"
 
 [[package]]
 name = "openssl"
-version = "0.10.72"
+version = "0.10.66"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fedfea7d58a1f73118430a55da6a286e7b044961736ce96a16a17068ea25e5da"
+checksum = "9529f4786b70a3e8c61e11179af17ab6188ad8d0ded78c5529441ed39d4bd9c1"
 dependencies = [
  "bitflags 2.6.0",
  "cfg-if",
@@ -1573,23 +1580,23 @@ checksum = "a948666b637a0f465e8564c73e89d4dde00d72d4d473cc972f390fc3dcee7d9c"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
 name = "openssl-src"
-version = "300.4.2+3.4.1"
+version = "300.5.1+3.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "168ce4e058f975fe43e89d9ccf78ca668601887ae736090aacc23ae353c298e2"
+checksum = "735230c832b28c000e3bc117119e6466a663ec73506bc0a9907ea4187508e42a"
 dependencies = [
  "cc",
 ]
 
 [[package]]
 name = "openssl-sys"
-version = "0.9.107"
+version = "0.9.103"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8288979acd84749c744a9014b4382d42b8f7b2592847b5afb2ed29e5d16ede07"
+checksum = "7f9e8deee91df40a943c71b917e5874b951d32a802526c85721ce3b776c929d6"
 dependencies = [
  "cc",
  "libc",
@@ -1779,7 +1786,7 @@ dependencies = [
  "polkavm-common",
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -1789,7 +1796,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8ba81f7b5faac81e528eb6158a6f3c9e0bb1008e0ffa19653bc8dea925ecb429"
 dependencies = [
  "polkavm-derive-impl",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -1814,7 +1821,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "479cf940fbbb3426c32c5d5176f62ad57549a0bb84773423ba8be9d089f5faba"
 dependencies = [
  "proc-macro2",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -1847,9 +1854,9 @@ checksum = "dc375e1527247fe1a97d8b7156678dfe7c1af2fc075c9a4db3690ecd2a148068"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.92"
+version = "1.0.86"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "37d3544b3f2748c54e147655edb5025752e2303145b5aefb3c3ea2c78b973bb0"
+checksum = "5e719e8df665df0d1c8fbfd238015744736151d4445ec0836b8e628aae103b77"
 dependencies = [
  "unicode-ident",
 ]
@@ -1901,7 +1908,7 @@ dependencies = [
  "proc-macro2",
  "pyo3-macros-backend",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -1914,7 +1921,7 @@ dependencies = [
  "proc-macro2",
  "pyo3-build-config",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -1981,7 +1988,7 @@ checksum = "8b86292cf41ccfc96c5de7165c1c53d5b4ac540c5bab9d1857acbe9eba5f1a0b"
 dependencies = [
  "proc-macro-hack",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -2030,7 +2037,7 @@ checksum = "bcc303e793d3734489387d205e9b186fac9c6cfacedd98cbb2e8a5943595f3e6"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -2089,23 +2096,23 @@ dependencies = [
 
 [[package]]
 name = "rpassword"
-version = "7.3.1"
+version = "7.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "80472be3c897911d0137b2d2b9055faf6eeac5b14e324073d83bc17b191d7e3f"
+checksum = "66d4c8b64f049c6721ec8ccec37ddfc3d641c4a7fca57e8f2a89de509c73df39"
 dependencies = [
  "libc",
  "rtoolbox",
- "windows-sys 0.48.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
 name = "rtoolbox"
-version = "0.0.2"
+version = "0.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c247d24e63230cdb56463ae328478bd5eac8b8faa8c69461a77e8e323afac90e"
+checksum = "a7cc970b249fbe527d6e02e0a227762c9108b2f49d81094fe357ffc6d14d7f6f"
 dependencies = [
  "libc",
- "windows-sys 0.48.0",
+ "windows-sys 0.52.0",
 ]
 
 [[package]]
@@ -2284,7 +2291,7 @@ checksum = "243902eda00fad750862fc144cea25caca5e20d615af0a81bee94ca738f1df1f"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -2479,7 +2486,7 @@ checksum = "48d09fa0a5f7299fb81ee25ae3853d26200f7a348148aed6de76be905c007dbe"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -2524,7 +2531,7 @@ dependencies = [
  "proc-macro-crate",
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -2638,9 +2645,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "2.0.89"
+version = "2.0.87"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "44d46482f1c1c87acd84dea20c1bf5ebff4c757009ed6bf19cfd36fb10e92c4e"
+checksum = "25aa4ce346d03a6dcd68dd8b4010bcb74e54e62c90c573f394c46eae99aba32d"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2670,11 +2677,11 @@ dependencies = [
 
 [[package]]
 name = "thiserror"
-version = "2.0.3"
+version = "2.0.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c006c85c7651b3cf2ada4584faa36773bd07bac24acfb39f3c431b36d7e667aa"
+checksum = "567b8a2dae586314f7be2a752ec7474332959c6460e02bde30d702a66d488708"
 dependencies = [
- "thiserror-impl 2.0.3",
+ "thiserror-impl 2.0.12",
 ]
 
 [[package]]
@@ -2685,18 +2692,18 @@ checksum = "08904e7672f5eb876eaaf87e0ce17857500934f4981c4a0ab2b4aa98baac7fc3"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
 name = "thiserror-impl"
-version = "2.0.3"
+version = "2.0.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f077553d607adc1caf65430528a576c757a71ed73944b66ebb58ef2bbd243568"
+checksum = "7f7cf42b4507d8ea322120659672cf1b9dbb93f8f2d4ecfd6e51350ff5b17a1d"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -2760,7 +2767,7 @@ checksum = "34704c8d6ebcbc939824180af020566b01a7c01f80641264eba0999f6c2b6be7"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -2959,7 +2966,7 @@ dependencies = [
  "once_cell",
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
  "wasm-bindgen-shared",
 ]
 
@@ -2981,7 +2988,7 @@ checksum = "afc340c74d9005395cf9dd098506f7f44e38f2b4a21c6aaacf9a105ea5e1e836"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
  "wasm-bindgen-backend",
  "wasm-bindgen-shared",
 ]
@@ -3041,6 +3048,15 @@ dependencies = [
  "windows-targets 0.48.5",
 ]
 
+[[package]]
+name = "windows-sys"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "282be5f36a8ce781fad8c8ae18fa3f9beff57ec1b52cb3de0789201425d9a33d"
+dependencies = [
+ "windows-targets 0.52.6",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.59.0"
@@ -3207,7 +3223,7 @@ checksum = "fa4f8080344d4671fb4e831a13ad1e68092748387dfc4f55e356242fae12ce3e"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
 
 [[package]]
@@ -3227,5 +3243,5 @@ checksum = "ce36e65b0d2999d2aafac989fb249189a141aee1f53c612c1f37d72631959f69"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.89",
+ "syn 2.0.87",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index 5f16e210..4c3672d7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "bittensor_wallet"
-version = "3.1.0"
+version = "4.0.0"
 edition = "2021"
 
 [lib]
diff --git a/src/keypair.rs b/src/keypair.rs
index 7febd7ef..ceca1e37 100644
--- a/src/keypair.rs
+++ b/src/keypair.rs
@@ -28,7 +28,7 @@ struct Meta {
     genesis_hash: Option<String>,
     name: String,
     #[serde(rename = "whenCreated")]
-    when_created: u64,
+    when_created: Option<u64>,
 }
 
 #[derive(Serialize, Deserialize, Debug)]
diff --git a/src/wallet.rs b/src/wallet.rs
index be652c6f..5edf13e8 100644
--- a/src/wallet.rs
+++ b/src/wallet.rs
@@ -320,13 +320,13 @@ impl Wallet {
     pub fn hotkeypub_file(&self) -> Result<Keyfile, KeyFileError> {
         // concatenate wallet path
         let wallet_path = self._path.join(&self.name);
-
+        let hotkeypub_name = format!("{}pub.txt", self.hotkey);
         // concatenate hotkeypub path
-        let hotkeypub_path = wallet_path.join("hotkeypub.txt");
+        let hotkeypub_path = wallet_path.join("hotkeys").join(&hotkeypub_name);
 
         Keyfile::new(
             hotkeypub_path.to_string_lossy().into_owned(),
-            Some("hotkeypub.txt".to_string()),
+            Some(hotkeypub_name),
             false,
         )
     }
@@ -606,7 +606,7 @@ impl Wallet {
         let _hotkeypub = self
             ._hotkeypub
             .clone()
-            .ok_or_else(|| KeyFileError::Generic("Hotkey file doesn't exist.".to_string()))?;
+            .ok_or_else(|| KeyFileError::Generic("Hotkeypub file doesn't exist.".to_string()))?;
         Ok(_hotkeypub)
     }
 
diff --git a/tests/test_wallet.py b/tests/test_wallet.py
index 7dbb28f5..7e2dc26d 100644
--- a/tests/test_wallet.py
+++ b/tests/test_wallet.py
@@ -156,14 +156,18 @@ def test_unlock_coldkeypub(mock_wallet):
     """Verify that `unlock_coldkeypub` works correctly."""
     # Call
     coldkeypub = mock_wallet.unlock_coldkeypub()
-    hotkeypub = mock_wallet.unlock_hotkeypub()
 
     # Assertions
     assert coldkeypub.ss58_address == mock_wallet.get_coldkeypub().ss58_address
     assert coldkeypub.public_key == mock_wallet.get_coldkeypub().public_key
     assert coldkeypub.ss58_format == mock_wallet.get_coldkeypub().ss58_format
     assert coldkeypub.crypto_type == mock_wallet.get_coldkeypub().crypto_type
-
+    
+def test_unlock_hotkeypub(mock_wallet):
+    # Call
+    hotkeypub = mock_wallet.unlock_hotkeypub()
+    
+    # Assertations
     assert hotkeypub.ss58_address == mock_wallet.get_hotkeypub().ss58_address
     assert hotkeypub.public_key == mock_wallet.get_hotkeypub().public_key
     assert hotkeypub.ss58_format == mock_wallet.get_hotkeypub().ss58_format