diff --git a/CHANGELOG.md b/CHANGELOG.md
index d671bc489..4bee58ae2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [4.0.0-rc.1]
+
+### Changed
+- Run wasm-opt first, remove sign_ext feature - [#1416](https://github.com/paritytech/cargo-contract/pull/1416)
+
 ## [4.0.0-rc]
 
 ### Added
diff --git a/Cargo.lock b/Cargo.lock
index b98ca7f13..96f561c56 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -326,7 +326,7 @@ dependencies = [
  "futures-lite 2.0.1",
  "parking",
  "polling 3.3.1",
- "rustix 0.38.25",
+ "rustix 0.38.26",
  "slab",
  "tracing",
  "windows-sys 0.52.0",
@@ -376,7 +376,7 @@ dependencies = [
  "cfg-if",
  "event-listener 3.1.0",
  "futures-lite 1.13.0",
- "rustix 0.38.25",
+ "rustix 0.38.26",
  "windows-sys 0.48.0",
 ]
 
@@ -392,7 +392,7 @@ dependencies = [
  "cfg-if",
  "futures-core",
  "futures-io",
- "rustix 0.38.25",
+ "rustix 0.38.26",
  "signal-hook-registry",
  "slab",
  "windows-sys 0.48.0",
@@ -805,7 +805,7 @@ dependencies = [
 
 [[package]]
 name = "cargo-contract"
-version = "4.0.0-rc"
+version = "4.0.0-rc.1"
 dependencies = [
  "anyhow",
  "assert_cmd",
@@ -1052,7 +1052,7 @@ checksum = "f7144d30dcf0fafbce74250a3963025d8d52177934239851c917d29f1df280c2"
 
 [[package]]
 name = "contract-analyze"
-version = "4.0.0-rc"
+version = "4.0.0-rc.1"
 dependencies = [
  "anyhow",
  "contract-metadata",
@@ -1062,7 +1062,7 @@ dependencies = [
 
 [[package]]
 name = "contract-build"
-version = "4.0.0-rc"
+version = "4.0.0-rc.1"
 dependencies = [
  "anyhow",
  "blake2",
@@ -1102,7 +1102,7 @@ dependencies = [
 
 [[package]]
 name = "contract-extrinsics"
-version = "4.0.0-rc"
+version = "4.0.0-rc.1"
 dependencies = [
  "anyhow",
  "assert_cmd",
@@ -1137,7 +1137,7 @@ dependencies = [
 
 [[package]]
 name = "contract-metadata"
-version = "4.0.0-rc"
+version = "4.0.0-rc.1"
 dependencies = [
  "anyhow",
  "impl-serde",
@@ -1150,7 +1150,7 @@ dependencies = [
 
 [[package]]
 name = "contract-transcode"
-version = "4.0.0-rc"
+version = "4.0.0-rc.1"
 dependencies = [
  "anyhow",
  "assert_matches",
@@ -1186,9 +1186,9 @@ checksum = "6245d59a3e82a7fc217c5828a6692dbc6dfb63a0c8c90495621f7b9d79704a0e"
 
 [[package]]
 name = "core-foundation"
-version = "0.9.3"
+version = "0.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "194a7a9e6de53fa55116934067c844d9d749312f75c6f6d0980e8c252f8c2146"
+checksum = "91e195e091a93c46f7102ec7818a2aa394e1e1771c3ab4825963fa03e45afb8f"
 dependencies = [
  "core-foundation-sys",
  "libc",
@@ -1196,9 +1196,9 @@ dependencies = [
 
 [[package]]
 name = "core-foundation-sys"
-version = "0.8.4"
+version = "0.8.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e496a50fda8aacccc86d7529e2c1e0892dbd0f898a6b5645b5561b89c3210efa"
+checksum = "06ea2b9bc92be3c2baa9334a323ebca2d6f074ff852cd1d7b11064035cd3868f"
 
 [[package]]
 name = "cpp_demangle"
@@ -2645,7 +2645,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cb0889898416213fab133e1d33a0e5858a48177452750691bde3666d0fdbaf8b"
 dependencies = [
  "hermit-abi",
- "rustix 0.38.25",
+ "rustix 0.38.26",
  "windows-sys 0.48.0",
 ]
 
@@ -2951,9 +2951,9 @@ checksum = "ef53942eb7bf7ff43a617b3e2c1c4a5ecf5944a7c1bc12d7ee39bbb15e5c1519"
 
 [[package]]
 name = "linux-raw-sys"
-version = "0.4.11"
+version = "0.4.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "969488b55f8ac402214f3f5fd243ebb7206cf82de60d3172994707a4bcc2b829"
+checksum = "c4cd1a83af159aa67994778be9070f0ae1bd732942279cabb14f86f986a21456"
 
 [[package]]
 name = "lock_api"
@@ -3016,7 +3016,7 @@ version = "0.6.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b2cffa4ad52c6f791f4f8b15f0c05f9824b2ced1160e88cc393d64fff9a8ac64"
 dependencies = [
- "rustix 0.38.25",
+ "rustix 0.38.26",
 ]
 
 [[package]]
@@ -3503,7 +3503,7 @@ dependencies = [
  "cfg-if",
  "concurrent-queue",
  "pin-project-lite",
- "rustix 0.38.25",
+ "rustix 0.38.26",
  "tracing",
  "windows-sys 0.52.0",
 ]
@@ -4002,15 +4002,15 @@ dependencies = [
 
 [[package]]
 name = "rustix"
-version = "0.38.25"
+version = "0.38.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dc99bc2d4f1fed22595588a013687477aedf3cdcfb26558c559edb67b4d9b22e"
+checksum = "9470c4bf8246c8daf25f9598dca807fb6510347b1e1cfa55749113850c79d88a"
 dependencies = [
  "bitflags 2.4.1",
  "errno",
  "libc",
- "linux-raw-sys 0.4.11",
- "windows-sys 0.48.0",
+ "linux-raw-sys 0.4.12",
+ "windows-sys 0.52.0",
 ]
 
 [[package]]
@@ -5489,7 +5489,7 @@ dependencies = [
  "cfg-if",
  "fastrand 2.0.1",
  "redox_syscall",
- "rustix 0.38.25",
+ "rustix 0.38.26",
  "windows-sys 0.48.0",
 ]
 
@@ -6422,7 +6422,7 @@ dependencies = [
  "either",
  "home",
  "once_cell",
- "rustix 0.38.25",
+ "rustix 0.38.26",
  "windows-sys 0.48.0",
 ]
 
@@ -6712,18 +6712,18 @@ checksum = "ff4524214bc4629eba08d78ceb1d6507070cc0bcbbed23af74e19e6e924a24cf"
 
 [[package]]
 name = "zerocopy"
-version = "0.7.26"
+version = "0.7.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e97e415490559a91254a2979b4829267a57d2fcd741a98eee8b722fb57289aa0"
+checksum = "7d6f15f7ade05d2a4935e34a457b936c23dc70a05cc1d97133dc99e7a3fe0f0e"
 dependencies = [
  "zerocopy-derive",
 ]
 
 [[package]]
 name = "zerocopy-derive"
-version = "0.7.26"
+version = "0.7.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dd7e48ccf166952882ca8bd778a43502c64f33bf94c12ebe2a7f08e5a0f6689f"
+checksum = "dbbad221e3f78500350ecbd7dfa4e63ef945c05f4c61cb7f4d3f84cd0bba649b"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/crates/analyze/Cargo.toml b/crates/analyze/Cargo.toml
index 6b8d4e895..8d82b05e1 100644
--- a/crates/analyze/Cargo.toml
+++ b/crates/analyze/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "contract-analyze"
-version = "4.0.0-rc"
+version = "4.0.0-rc.1"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2021"
 
@@ -14,7 +14,7 @@ keywords = ["wasm", "parity", "webassembly", "blockchain", "edsl"]
 include = ["Cargo.toml", "*.rs", "LICENSE"]
 
 [dependencies]
-contract-metadata = { version = "4.0.0-rc", path = "../metadata" }
+contract-metadata = { version = "4.0.0-rc.1", path = "../metadata" }
 parity-wasm = { version = "0.45.0" }
 anyhow = "1.0.75"
 
diff --git a/crates/build/Cargo.toml b/crates/build/Cargo.toml
index a8051ba26..7b40677a3 100644
--- a/crates/build/Cargo.toml
+++ b/crates/build/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "contract-build"
-version = "4.0.0-rc"
+version = "4.0.0-rc.1"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2021"
 
@@ -44,7 +44,7 @@ tokio-stream = "0.1"
 bollard = "0.15"
 crossterm = "0.27.0"
 
-contract-metadata = { version = "4.0.0-rc", path = "../metadata" }
+contract-metadata = { version = "4.0.0-rc.1", path = "../metadata" }
 
 [target.'cfg(unix)'.dependencies]
 users = "0.11"
diff --git a/crates/cargo-contract/Cargo.toml b/crates/cargo-contract/Cargo.toml
index bd56c6873..19250c514 100644
--- a/crates/cargo-contract/Cargo.toml
+++ b/crates/cargo-contract/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "cargo-contract"
-version = "4.0.0-rc"
+version = "4.0.0-rc.1"
 authors = ["Parity Technologies <admin@parity.io>"]
 build = "build.rs"
 edition = "2021"
@@ -18,11 +18,11 @@ include = [
 ]
 
 [dependencies]
-contract-build = { version = "4.0.0-rc", path = "../build" }
-contract-extrinsics = { version = "4.0.0-rc", path = "../extrinsics" }
-contract-transcode = { version = "4.0.0-rc", path = "../transcode" }
-contract-metadata = { version = "4.0.0-rc", path = "../metadata" }
-contract-analyze = { version = "4.0.0-rc", path = "../analyze" }
+contract-build = { version = "4.0.0-rc.1", path = "../build" }
+contract-extrinsics = { version = "4.0.0-rc.1", path = "../extrinsics" }
+contract-transcode = { version = "4.0.0-rc.1", path = "../transcode" }
+contract-metadata = { version = "4.0.0-rc.1", path = "../metadata" }
+contract-analyze = { version = "4.0.0-rc.1", path = "../analyze" }
 
 anyhow = "1.0.75"
 clap = { version = "4.4.10", features = ["derive", "env"] }
diff --git a/crates/extrinsics/Cargo.toml b/crates/extrinsics/Cargo.toml
index 2e4fe9494..372a668e0 100644
--- a/crates/extrinsics/Cargo.toml
+++ b/crates/extrinsics/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "contract-extrinsics"
-version = "4.0.0-rc"
+version = "4.0.0-rc.1"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2021"
 rust-version = "1.70"
@@ -15,9 +15,9 @@ keywords = ["wasm", "parity", "webassembly", "blockchain", "edsl"]
 include = ["Cargo.toml", "*.rs", "LICENSE",]
 
 [dependencies]
-contract-build = { version = "4.0.0-rc", path = "../build" }
-contract-metadata = { version = "4.0.0-rc", path = "../metadata" }
-contract-transcode = { version = "4.0.0-rc", path = "../transcode" }
+contract-build = { version = "4.0.0-rc.1", path = "../build" }
+contract-metadata = { version = "4.0.0-rc.1", path = "../metadata" }
+contract-transcode = { version = "4.0.0-rc.1", path = "../transcode" }
 
 anyhow = "1.0.75"
 blake2 = { version = "0.10.6", default-features = false }
diff --git a/crates/metadata/Cargo.toml b/crates/metadata/Cargo.toml
index 4ccbb298e..229e46891 100644
--- a/crates/metadata/Cargo.toml
+++ b/crates/metadata/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "contract-metadata"
-version = "4.0.0-rc"
+version = "4.0.0-rc.1"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2021"
 
diff --git a/crates/metadata/compatibility_list.json b/crates/metadata/compatibility_list.json
index 36da15fb3..302275cd1 100644
--- a/crates/metadata/compatibility_list.json
+++ b/crates/metadata/compatibility_list.json
@@ -11,6 +11,9 @@
         },
         "4.0.0-rc": {
             "ink": ["5.0.0-alpha", "5.0.0"]
+        },
+        "4.0.0-rc.1": {
+            "ink": ["5.0.0-alpha", "5.0.0"]
         }
     }
 }
diff --git a/crates/transcode/Cargo.toml b/crates/transcode/Cargo.toml
index 1fd1a6984..11c8cc611 100644
--- a/crates/transcode/Cargo.toml
+++ b/crates/transcode/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "contract-transcode"
-version = "4.0.0-rc"
+version = "4.0.0-rc.1"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2021"
 
@@ -20,7 +20,7 @@ path = "src/lib.rs"
 anyhow = "1.0.75"
 base58 = { version = "0.2.0" }
 blake2 = { version = "0.10.6", default-features = false }
-contract-metadata = { version = "4.0.0-rc", path = "../metadata" }
+contract-metadata = { version = "4.0.0-rc.1", path = "../metadata" }
 escape8259 = "0.5.2"
 hex = "0.4.3"
 indexmap = "2.1.0"