diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 9c2b0364d..2be24a71f 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -27,7 +27,7 @@ jobs:
         uses: actions-rs/cargo@v1
         with:
           command: test
-          args: --locked --verbose
+          args: --locked --verbose --features meta-call
   bully-build:
     name: Bully build
     runs-on: ubuntu-latest
diff --git a/CHANGES.md b/CHANGES.md
index 8798d8b86..89d5381ab 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -5,6 +5,8 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.4.1] - 2021-06-23
+
 ## [1.4.0] - 2021-06-18
 
 ## [1.3.0] - 2021-06-17
@@ -15,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [1.0.0] - 2021-05-12
 
+[1.4.1]: https://github.com/aurora-is-near/aurora-engine/compare/1.4.0...1.4.1
 [1.4.0]: https://github.com/aurora-is-near/aurora-engine/compare/1.3.0...1.4.0
 [1.3.0]: https://github.com/aurora-is-near/aurora-engine/compare/1.2.0...1.3.0
 [1.2.0]: https://github.com/aurora-is-near/aurora-engine/compare/1.1.0...1.2.0
diff --git a/Cargo.lock b/Cargo.lock
index 86bcf7fe6..21e681d2d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -8,15 +8,6 @@ version = "0.11.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fe438c63458706e03479442743baae6c88256498e6431708f6dfc520a26515d3"
 
-[[package]]
-name = "addr2line"
-version = "0.14.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a55f82cfe485775d02112886f4169bde0c5894d75e79ead7eafe7e40a25e45f7"
-dependencies = [
- "gimli 0.23.0",
-]
-
 [[package]]
 name = "addr2line"
 version = "0.15.1"
@@ -132,12 +123,12 @@ dependencies = [
  "lazy-static-include",
  "libsecp256k1",
  "logos",
- "near-crypto 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "near-primitives-core 0.1.0 (git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f)",
+ "near-crypto",
+ "near-primitives-core 0.4.0",
  "near-sdk",
  "near-sdk-sim",
- "near-vm-logic 3.0.0 (git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f)",
- "near-vm-runner 3.0.0",
+ "near-vm-logic 4.0.0-pre.1",
+ "near-vm-runner",
  "num",
  "primitive-types",
  "rand 0.7.3",
@@ -163,7 +154,7 @@ version = "0.3.59"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4717cfcbfaa661a0fd48f8453951837ae7e8f81e481fbb136e3202d72805a744"
 dependencies = [
- "addr2line 0.15.1",
+ "addr2line",
  "cc",
  "cfg-if 1.0.0",
  "libc",
@@ -551,16 +542,6 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6245d59a3e82a7fc217c5828a6692dbc6dfb63a0c8c90495621f7b9d79704a0e"
 
-[[package]]
-name = "cpp_demangle"
-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "44919ecaf6f99e8e737bc239408931c9a01e9a6c74814fee8242dd2506b65390"
-dependencies = [
- "cfg-if 1.0.0",
- "glob",
-]
-
 [[package]]
 name = "cpufeatures"
 version = "0.1.1"
@@ -588,15 +569,6 @@ dependencies = [
  "cranelift-entity 0.68.0",
 ]
 
-[[package]]
-name = "cranelift-bforest"
-version = "0.72.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "841476ab6d3530136b5162b64a2c6969d68141843ad2fd59126e5ea84fd9b5fe"
-dependencies = [
- "cranelift-entity 0.72.0",
-]
-
 [[package]]
 name = "cranelift-codegen"
 version = "0.67.0"
@@ -636,26 +608,6 @@ dependencies = [
  "thiserror",
 ]
 
-[[package]]
-name = "cranelift-codegen"
-version = "0.72.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2b5619cef8d19530298301f91e9a0390d369260799a3d8dd01e28fc88e53637a"
-dependencies = [
- "byteorder",
- "cranelift-bforest 0.72.0",
- "cranelift-codegen-meta 0.72.0",
- "cranelift-codegen-shared 0.72.0",
- "cranelift-entity 0.72.0",
- "gimli 0.23.0",
- "log",
- "regalloc 0.0.31",
- "serde",
- "smallvec",
- "target-lexicon 0.11.2",
- "thiserror",
-]
-
 [[package]]
 name = "cranelift-codegen-meta"
 version = "0.67.0"
@@ -676,16 +628,6 @@ dependencies = [
  "cranelift-entity 0.68.0",
 ]
 
-[[package]]
-name = "cranelift-codegen-meta"
-version = "0.72.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2a319709b8267939155924114ea83f2a5b5af65ece3ac6f703d4735f3c66bb0d"
-dependencies = [
- "cranelift-codegen-shared 0.72.0",
- "cranelift-entity 0.72.0",
-]
-
 [[package]]
 name = "cranelift-codegen-shared"
 version = "0.67.0"
@@ -698,15 +640,6 @@ version = "0.68.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6759012d6d19c4caec95793f052613e9d4113e925e7f14154defbac0f1d4c938"
 
-[[package]]
-name = "cranelift-codegen-shared"
-version = "0.72.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "15925b23cd3a448443f289d85a8f53f3cf7a80f0137aa53c8e3b01ae8aefaef7"
-dependencies = [
- "serde",
-]
-
 [[package]]
 name = "cranelift-entity"
 version = "0.67.0"
@@ -725,15 +658,6 @@ dependencies = [
  "serde",
 ]
 
-[[package]]
-name = "cranelift-entity"
-version = "0.72.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "610cf464396c89af0f9f7c64b5aa90aa9e8812ac84084098f1565b40051bc415"
-dependencies = [
- "serde",
-]
-
 [[package]]
 name = "cranelift-frontend"
 version = "0.67.0"
@@ -758,18 +682,6 @@ dependencies = [
  "target-lexicon 0.11.2",
 ]
 
-[[package]]
-name = "cranelift-frontend"
-version = "0.72.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4d20c8bd4a1c41ded051734f0e33ad1d843a0adc98b9bd975ee6657e2c70cdc9"
-dependencies = [
- "cranelift-codegen 0.72.0",
- "log",
- "smallvec",
- "target-lexicon 0.11.2",
-]
-
 [[package]]
 name = "cranelift-native"
 version = "0.67.0"
@@ -781,16 +693,6 @@ dependencies = [
  "target-lexicon 0.11.2",
 ]
 
-[[package]]
-name = "cranelift-native"
-version = "0.72.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "304e100df41f34a5a15291b37bfe0fd7abd0427a2c84195cc69578b4137f9099"
-dependencies = [
- "cranelift-codegen 0.72.0",
- "target-lexicon 0.11.2",
-]
-
 [[package]]
 name = "cranelift-wasm"
 version = "0.67.0"
@@ -806,23 +708,6 @@ dependencies = [
  "wasmparser 0.59.0",
 ]
 
-[[package]]
-name = "cranelift-wasm"
-version = "0.72.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4efd473b2917303957e0bfaea6ea9d08b8c93695bee015a611a2514ce5254abc"
-dependencies = [
- "cranelift-codegen 0.72.0",
- "cranelift-entity 0.72.0",
- "cranelift-frontend 0.72.0",
- "itertools 0.10.0",
- "log",
- "serde",
- "smallvec",
- "thiserror",
- "wasmparser 0.76.0",
-]
-
 [[package]]
 name = "crc32fast"
 version = "1.2.1"
@@ -1534,17 +1419,6 @@ dependencies = [
  "stable_deref_trait",
 ]
 
-[[package]]
-name = "gimli"
-version = "0.23.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f6503fe142514ca4799d4c26297c4248239fe8838d827db6bd6065c6ed29a6ce"
-dependencies = [
- "fallible-iterator",
- "indexmap",
- "stable_deref_trait",
-]
-
 [[package]]
 name = "gimli"
 version = "0.24.0"
@@ -2055,30 +1929,6 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0debeb9fcf88823ea64d64e4a815ab1643f33127d995978e099942ce38f25238"
 
-[[package]]
-name = "near-crypto"
-version = "0.1.0"
-source = "git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f#3744f07e13bf43a9522fb39fa8f6f128396d0e1f"
-dependencies = [
- "arrayref",
- "blake2 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "borsh",
- "bs58",
- "c2-chacha",
- "curve25519-dalek",
- "derive_more",
- "ed25519-dalek",
- "lazy_static",
- "libc",
- "parity-secp256k1",
- "rand 0.7.3",
- "rand_core 0.5.1",
- "serde",
- "serde_json",
- "subtle 2.4.0",
- "thiserror",
-]
-
 [[package]]
 name = "near-crypto"
 version = "0.1.0"
@@ -2122,8 +1972,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bde79472f7cfc0675733b65f79f9e50c20bfbb9806298ab2872916869a45dccd"
 dependencies = [
  "borsh",
- "near-crypto 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "near-primitives 0.1.0-pre.1",
+ "near-crypto",
+ "near-primitives",
  "rand 0.7.3",
 ]
 
@@ -2143,9 +1993,9 @@ dependencies = [
  "hex",
  "jemallocator",
  "lazy_static",
- "near-crypto 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "near-crypto",
  "near-primitives-core 0.4.0",
- "near-rpc-error-macro 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "near-rpc-error-macro",
  "near-vm-errors 4.0.0-pre.1",
  "num-rational 0.3.2",
  "primitive-types",
@@ -2159,54 +2009,6 @@ dependencies = [
  "validator",
 ]
 
-[[package]]
-name = "near-primitives"
-version = "0.1.0"
-source = "git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f#3744f07e13bf43a9522fb39fa8f6f128396d0e1f"
-dependencies = [
- "base64 0.13.0",
- "borsh",
- "bs58",
- "byteorder",
- "chrono",
- "derive_more",
- "easy-ext",
- "hex",
- "jemallocator",
- "lazy_static",
- "near-crypto 0.1.0 (git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f)",
- "near-primitives-core 0.1.0 (git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f)",
- "near-rpc-error-macro 0.1.0 (git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f)",
- "near-vm-errors 3.0.0 (git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f)",
- "num-rational 0.3.2",
- "primitive-types",
- "rand 0.7.3",
- "reed-solomon-erasure",
- "regex",
- "serde",
- "serde_json",
- "sha2 0.9.5",
- "smart-default",
- "validator",
-]
-
-[[package]]
-name = "near-primitives-core"
-version = "0.1.0"
-source = "git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f#3744f07e13bf43a9522fb39fa8f6f128396d0e1f"
-dependencies = [
- "base64 0.11.0",
- "borsh",
- "bs58",
- "derive_more",
- "hex",
- "lazy_static",
- "num-rational 0.3.2",
- "serde",
- "serde_json",
- "sha2 0.9.5",
-]
-
 [[package]]
 name = "near-primitives-core"
 version = "0.1.0"
@@ -2243,17 +2045,6 @@ dependencies = [
  "sha2 0.9.5",
 ]
 
-[[package]]
-name = "near-rpc-error-core"
-version = "0.1.0"
-source = "git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f#3744f07e13bf43a9522fb39fa8f6f128396d0e1f"
-dependencies = [
- "proc-macro2",
- "quote",
- "serde",
- "syn",
-]
-
 [[package]]
 name = "near-rpc-error-core"
 version = "0.1.0"
@@ -2267,26 +2058,13 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "near-rpc-error-macro"
-version = "0.1.0"
-source = "git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f#3744f07e13bf43a9522fb39fa8f6f128396d0e1f"
-dependencies = [
- "near-rpc-error-core 0.1.0 (git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f)",
- "proc-macro2",
- "quote",
- "serde",
- "serde_json",
- "syn",
-]
-
 [[package]]
 name = "near-rpc-error-macro"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0c6111d713e90c7c551dee937f4a06cb9ea2672243455a4454cc7566387ba2d9"
 dependencies = [
- "near-rpc-error-core 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "near-rpc-error-core",
  "proc-macro2",
  "quote",
  "serde",
@@ -2306,14 +2084,14 @@ dependencies = [
  "hex",
  "lazy_static",
  "log",
- "near-crypto 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "near-crypto",
  "near-metrics",
- "near-primitives 0.1.0-pre.1",
+ "near-primitives",
  "near-runtime-utils 4.0.0-pre.1",
  "near-store",
  "near-vm-errors 4.0.0-pre.1",
  "near-vm-logic 4.0.0-pre.1",
- "near-vm-runner 4.0.0-pre.1",
+ "near-vm-runner",
  "num-bigint 0.3.2",
  "num-rational 0.3.2",
  "num-traits",
@@ -2322,15 +2100,6 @@ dependencies = [
  "serde_json",
 ]
 
-[[package]]
-name = "near-runtime-utils"
-version = "3.0.0"
-source = "git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f#3744f07e13bf43a9522fb39fa8f6f128396d0e1f"
-dependencies = [
- "lazy_static",
- "regex",
-]
-
 [[package]]
 name = "near-runtime-utils"
 version = "3.0.0"
@@ -2359,9 +2128,9 @@ dependencies = [
  "base64 0.13.0",
  "borsh",
  "bs58",
- "near-primitives-core 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "near-primitives-core 0.1.0",
  "near-sdk-macros",
- "near-vm-logic 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "near-vm-logic 3.0.0",
  "serde",
  "serde_json",
  "wee_alloc",
@@ -2396,9 +2165,9 @@ source = "git+https://github.com/near/near-sdk-rs?rev=9d99077c6acfde68c06845f2a1
 dependencies = [
  "funty",
  "lazy-static-include",
- "near-crypto 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "near-crypto",
  "near-pool",
- "near-primitives 0.1.0-pre.1",
+ "near-primitives",
  "near-runtime",
  "near-sdk",
  "near-store",
@@ -2417,8 +2186,8 @@ dependencies = [
  "derive_more",
  "elastic-array",
  "lazy_static",
- "near-crypto 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "near-primitives 0.1.0-pre.1",
+ "near-crypto",
+ "near-primitives",
  "num_cpus",
  "rand 0.7.3",
  "rocksdb",
@@ -2427,17 +2196,6 @@ dependencies = [
  "strum",
 ]
 
-[[package]]
-name = "near-vm-errors"
-version = "3.0.0"
-source = "git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f#3744f07e13bf43a9522fb39fa8f6f128396d0e1f"
-dependencies = [
- "borsh",
- "hex",
- "near-rpc-error-macro 0.1.0 (git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f)",
- "serde",
-]
-
 [[package]]
 name = "near-vm-errors"
 version = "3.0.0"
@@ -2446,7 +2204,7 @@ checksum = "53a100dda565c5375ac061126167afc5c33cdba1f2e325cfae3ce08f4a5a432a"
 dependencies = [
  "borsh",
  "hex",
- "near-rpc-error-macro 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "near-rpc-error-macro",
  "serde",
 ]
 
@@ -2458,25 +2216,8 @@ checksum = "e281d8730ed8cb0e3e69fb689acee6b93cdb43824cd69a8ffd7e1bfcbd1177d7"
 dependencies = [
  "borsh",
  "hex",
- "near-rpc-error-macro 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde",
-]
-
-[[package]]
-name = "near-vm-logic"
-version = "3.0.0"
-source = "git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f#3744f07e13bf43a9522fb39fa8f6f128396d0e1f"
-dependencies = [
- "base64 0.13.0",
- "borsh",
- "bs58",
- "byteorder",
- "near-primitives-core 0.1.0 (git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f)",
- "near-runtime-utils 3.0.0 (git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f)",
- "near-vm-errors 3.0.0 (git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f)",
+ "near-rpc-error-macro",
  "serde",
- "sha2 0.9.5",
- "sha3 0.9.1",
 ]
 
 [[package]]
@@ -2489,9 +2230,9 @@ dependencies = [
  "borsh",
  "bs58",
  "byteorder",
- "near-primitives-core 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "near-runtime-utils 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "near-vm-errors 3.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "near-primitives-core 0.1.0",
+ "near-runtime-utils 3.0.0",
+ "near-vm-errors 3.0.0",
  "serde",
  "sha2 0.9.5",
  "sha3 0.9.1",
@@ -2515,33 +2256,6 @@ dependencies = [
  "sha3 0.9.1",
 ]
 
-[[package]]
-name = "near-vm-runner"
-version = "3.0.0"
-source = "git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f#3744f07e13bf43a9522fb39fa8f6f128396d0e1f"
-dependencies = [
- "anyhow",
- "borsh",
- "cached",
- "near-primitives 0.1.0",
- "near-vm-errors 3.0.0 (git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f)",
- "near-vm-logic 3.0.0 (git+https://github.com/near/nearcore?rev=3744f07e13bf43a9522fb39fa8f6f128396d0e1f)",
- "parity-wasm",
- "pwasm-utils",
- "serde",
- "threadpool",
- "tracing",
- "wasmer",
- "wasmer-compiler-cranelift",
- "wasmer-compiler-singlepass",
- "wasmer-engine-native",
- "wasmer-runtime-core-near",
- "wasmer-runtime-near",
- "wasmer-types",
- "wasmer-vm",
- "wasmtime 0.25.0",
-]
-
 [[package]]
 name = "near-vm-runner"
 version = "4.0.0-pre.1"
@@ -2552,7 +2266,7 @@ dependencies = [
  "borsh",
  "cached",
  "log",
- "near-primitives 0.1.0-pre.1",
+ "near-primitives",
  "near-vm-errors 4.0.0-pre.1",
  "near-vm-logic 4.0.0-pre.1",
  "parity-wasm",
@@ -2563,7 +2277,7 @@ dependencies = [
  "wasmer-runtime-core-near",
  "wasmer-runtime-near",
  "wasmer-types",
- "wasmtime 0.20.0",
+ "wasmtime",
 ]
 
 [[package]]
@@ -2720,16 +2434,6 @@ dependencies = [
  "indexmap",
 ]
 
-[[package]]
-name = "object"
-version = "0.23.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a9a7ab5d64814df0fe4a4b5ead45ed6c5f181ee3ff04ba344313a6c80446c5d4"
-dependencies = [
- "crc32fast",
- "indexmap",
-]
-
 [[package]]
 name = "object"
 version = "0.24.0"
@@ -2881,12 +2585,6 @@ dependencies = [
  "winapi",
 ]
 
-[[package]]
-name = "paste"
-version = "1.0.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "acbf547ad0c65e31259204bd90935776d1c693cec2f4ff7abb7a1bbbd40dfe58"
-
 [[package]]
 name = "peeking_take_while"
 version = "0.1.2"
@@ -3039,15 +2737,6 @@ version = "2.23.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "45604fc7a88158e7d514d8e22e14ac746081e7a70d7690074dd0029ee37458d6"
 
-[[package]]
-name = "psm"
-version = "0.1.12"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3abf49e5417290756acfd26501536358560c4a5cc4a0934d390939acb3e7083a"
-dependencies = [
- "cc",
-]
-
 [[package]]
 name = "pwasm-utils"
 version = "0.12.0"
@@ -3234,7 +2923,6 @@ checksum = "571f7f397d61c4755285cd37853fe8e03271c243424a907415909379659381c5"
 dependencies = [
  "log",
  "rustc-hash",
- "serde",
  "smallvec",
 ]
 
@@ -3683,15 +3371,6 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "threadpool"
-version = "1.8.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d050e60b33d41c19108b32cea32164033a9013fe3b46cbd4457559bfbf77afaa"
-dependencies = [
- "num_cpus",
-]
-
 [[package]]
 name = "time"
 version = "0.1.43"
@@ -4255,12 +3934,6 @@ version = "0.65.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "87cc2fe6350834b4e528ba0901e7aa405d78b89dc1fa3145359eb4de0e323fcf"
 
-[[package]]
-name = "wasmparser"
-version = "0.76.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "755a9a4afe3f6cccbbe6d7e965eef44cf260b001f93e547eba84255c1d0187d8"
-
 [[package]]
 name = "wasmtime"
 version = "0.20.0"
@@ -4280,38 +3953,10 @@ dependencies = [
  "smallvec",
  "target-lexicon 0.11.2",
  "wasmparser 0.59.0",
- "wasmtime-environ 0.20.0",
- "wasmtime-jit 0.20.0",
- "wasmtime-profiling 0.20.0",
- "wasmtime-runtime 0.20.0",
- "winapi",
-]
-
-[[package]]
-name = "wasmtime"
-version = "0.25.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "26ea2ad49bb047e10ca292f55cd67040bef14b676d07e7b04ed65fd312d52ece"
-dependencies = [
- "anyhow",
- "backtrace",
- "bincode",
- "cfg-if 1.0.0",
- "cpp_demangle",
- "indexmap",
- "libc",
- "log",
- "paste",
- "region",
- "rustc-demangle",
- "serde",
- "smallvec",
- "target-lexicon 0.11.2",
- "wasmparser 0.76.0",
- "wasmtime-environ 0.25.0",
- "wasmtime-jit 0.25.0",
- "wasmtime-profiling 0.25.0",
- "wasmtime-runtime 0.25.0",
+ "wasmtime-environ",
+ "wasmtime-jit",
+ "wasmtime-profiling",
+ "wasmtime-runtime",
  "winapi",
 ]
 
@@ -4324,22 +3969,8 @@ dependencies = [
  "cranelift-codegen 0.67.0",
  "cranelift-entity 0.67.0",
  "cranelift-frontend 0.67.0",
- "cranelift-wasm 0.67.0",
- "wasmtime-environ 0.20.0",
-]
-
-[[package]]
-name = "wasmtime-cranelift"
-version = "0.25.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5e769b80abbb89255926f69ba37085f7dd6608c980134838c3c89d7bf6e776bc"
-dependencies = [
- "cranelift-codegen 0.72.0",
- "cranelift-entity 0.72.0",
- "cranelift-frontend 0.72.0",
- "cranelift-wasm 0.72.0",
- "wasmparser 0.76.0",
- "wasmtime-environ 0.25.0",
+ "cranelift-wasm",
+ "wasmtime-environ",
 ]
 
 [[package]]
@@ -4355,23 +3986,7 @@ dependencies = [
  "target-lexicon 0.11.2",
  "thiserror",
  "wasmparser 0.59.0",
- "wasmtime-environ 0.20.0",
-]
-
-[[package]]
-name = "wasmtime-debug"
-version = "0.25.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "38501788c936a4932b0ddf61135963a4b7d1f549f63a6908ae56a1c86d74fc7b"
-dependencies = [
- "anyhow",
- "gimli 0.23.0",
- "more-asserts",
- "object 0.23.0",
- "target-lexicon 0.11.2",
- "thiserror",
- "wasmparser 0.76.0",
- "wasmtime-environ 0.25.0",
+ "wasmtime-environ",
 ]
 
 [[package]]
@@ -4384,7 +3999,7 @@ dependencies = [
  "cfg-if 0.1.10",
  "cranelift-codegen 0.67.0",
  "cranelift-entity 0.67.0",
- "cranelift-wasm 0.67.0",
+ "cranelift-wasm",
  "gimli 0.21.0",
  "indexmap",
  "log",
@@ -4394,27 +4009,6 @@ dependencies = [
  "wasmparser 0.59.0",
 ]
 
-[[package]]
-name = "wasmtime-environ"
-version = "0.25.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fae793ea1387b2fede277d209bb27285366df58f0a3ae9d59e58a7941dce60fa"
-dependencies = [
- "anyhow",
- "cfg-if 1.0.0",
- "cranelift-codegen 0.72.0",
- "cranelift-entity 0.72.0",
- "cranelift-wasm 0.72.0",
- "gimli 0.23.0",
- "indexmap",
- "log",
- "more-asserts",
- "region",
- "serde",
- "thiserror",
- "wasmparser 0.76.0",
-]
-
 [[package]]
 name = "wasmtime-jit"
 version = "0.20.0"
@@ -4426,8 +4020,8 @@ dependencies = [
  "cranelift-codegen 0.67.0",
  "cranelift-entity 0.67.0",
  "cranelift-frontend 0.67.0",
- "cranelift-native 0.67.0",
- "cranelift-wasm 0.67.0",
+ "cranelift-native",
+ "cranelift-wasm",
  "gimli 0.21.0",
  "log",
  "more-asserts",
@@ -4437,44 +4031,12 @@ dependencies = [
  "target-lexicon 0.11.2",
  "thiserror",
  "wasmparser 0.59.0",
- "wasmtime-cranelift 0.20.0",
- "wasmtime-debug 0.20.0",
- "wasmtime-environ 0.20.0",
- "wasmtime-obj 0.20.0",
- "wasmtime-profiling 0.20.0",
- "wasmtime-runtime 0.20.0",
- "winapi",
-]
-
-[[package]]
-name = "wasmtime-jit"
-version = "0.25.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9b3bd0fae8396473a68a1491559d61776127bb9bea75c9a6a6c038ae4a656eb2"
-dependencies = [
- "addr2line 0.14.1",
- "anyhow",
- "cfg-if 1.0.0",
- "cranelift-codegen 0.72.0",
- "cranelift-entity 0.72.0",
- "cranelift-frontend 0.72.0",
- "cranelift-native 0.72.0",
- "cranelift-wasm 0.72.0",
- "gimli 0.23.0",
- "log",
- "more-asserts",
- "object 0.23.0",
- "region",
- "serde",
- "target-lexicon 0.11.2",
- "thiserror",
- "wasmparser 0.76.0",
- "wasmtime-cranelift 0.25.0",
- "wasmtime-debug 0.25.0",
- "wasmtime-environ 0.25.0",
- "wasmtime-obj 0.25.0",
- "wasmtime-profiling 0.25.0",
- "wasmtime-runtime 0.25.0",
+ "wasmtime-cranelift",
+ "wasmtime-debug",
+ "wasmtime-environ",
+ "wasmtime-obj",
+ "wasmtime-profiling",
+ "wasmtime-runtime",
  "winapi",
 ]
 
@@ -4488,22 +4050,8 @@ dependencies = [
  "more-asserts",
  "object 0.21.1",
  "target-lexicon 0.11.2",
- "wasmtime-debug 0.20.0",
- "wasmtime-environ 0.20.0",
-]
-
-[[package]]
-name = "wasmtime-obj"
-version = "0.25.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a79fa098a3be8fabc50f5be60f8e47694d569afdc255de37850fc80295485012"
-dependencies = [
- "anyhow",
- "more-asserts",
- "object 0.23.0",
- "target-lexicon 0.11.2",
- "wasmtime-debug 0.25.0",
- "wasmtime-environ 0.25.0",
+ "wasmtime-debug",
+ "wasmtime-environ",
 ]
 
 [[package]]
@@ -4518,24 +4066,8 @@ dependencies = [
  "libc",
  "serde",
  "target-lexicon 0.11.2",
- "wasmtime-environ 0.20.0",
- "wasmtime-runtime 0.20.0",
-]
-
-[[package]]
-name = "wasmtime-profiling"
-version = "0.25.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d81e2106efeef4c01917fd16956a91d39bb78c07cf97027abdba9ca98da3f258"
-dependencies = [
- "anyhow",
- "cfg-if 1.0.0",
- "lazy_static",
- "libc",
- "serde",
- "target-lexicon 0.11.2",
- "wasmtime-environ 0.25.0",
- "wasmtime-runtime 0.25.0",
+ "wasmtime-environ",
+ "wasmtime-runtime",
 ]
 
 [[package]]
@@ -4555,31 +4087,7 @@ dependencies = [
  "more-asserts",
  "region",
  "thiserror",
- "wasmtime-environ 0.20.0",
- "winapi",
-]
-
-[[package]]
-name = "wasmtime-runtime"
-version = "0.25.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f747c656ca4680cad7846ae91c57d03f2dd4f4170da77a700df4e21f0d805378"
-dependencies = [
- "anyhow",
- "backtrace",
- "cc",
- "cfg-if 1.0.0",
- "indexmap",
- "lazy_static",
- "libc",
- "log",
- "memoffset 0.6.3",
- "more-asserts",
- "psm",
- "rand 0.7.3",
- "region",
- "thiserror",
- "wasmtime-environ 0.25.0",
+ "wasmtime-environ",
  "winapi",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index 11cca8ea8..0d08a3839 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -65,9 +65,9 @@ hex = { version = "0.4.3", default-features = false }
 near-sdk = { git = "https://github.com/near/near-sdk-rs", rev = "9d99077c6acfde68c06845f2a1eb2b5ed7983401" }
 near-sdk-sim = { git = "https://github.com/near/near-sdk-rs", rev = "9d99077c6acfde68c06845f2a1eb2b5ed7983401" }
 near-crypto = "0.1.0"
-near-vm-runner = { git = "https://github.com/near/nearcore", rev = "3744f07e13bf43a9522fb39fa8f6f128396d0e1f" }
-near-primitives-core = { git = "https://github.com/near/nearcore", rev = "3744f07e13bf43a9522fb39fa8f6f128396d0e1f" }
-near-vm-logic = { git = "https://github.com/near/nearcore", rev = "3744f07e13bf43a9522fb39fa8f6f128396d0e1f" }
+near-vm-runner = "4.0.0-pre.1"
+near-vm-logic = "4.0.0-pre.1"
+near-primitives-core = "0.4.0"
 libsecp256k1 = "0.3.5"
 rand = "0.7.3"
 criterion = "0.3.4"
@@ -78,11 +78,10 @@ base64 = "0.13.0"
 [features]
 default = ["sha2", "std"]
 std = ["borsh/std", "evm/std", "primitive-types/std", "rlp/std", "sha3/std", "ethabi/std", "logos/std", "bn/std"]
-engine = []
-contract = ["engine"]
+contract = []
 evm_bully = []
 log = []
-meta-call = ["contract"]
+meta-call = []
 integration-test = ["log"]
 mainnet = ["contract", "log"]
 testnet = ["contract", "log"]
diff --git a/Makefile b/Makefile
index 517d3058e..d8d9566cb 100644
--- a/Makefile
+++ b/Makefile
@@ -60,7 +60,7 @@ check-clippy:
 
 # test depends on release since `tests/test_upgrade.rs` includes `release.wasm`
 test: test-build
-	$(CARGO) test
+	$(CARGO) test --features meta-call
 
 format:
 	$(CARGO) fmt
diff --git a/etc/eth-contracts/contracts/EvmErc20.sol b/etc/eth-contracts/contracts/EvmErc20.sol
index c9759c4e3..83059cc06 100644
--- a/etc/eth-contracts/contracts/EvmErc20.sol
+++ b/etc/eth-contracts/contracts/EvmErc20.sol
@@ -1,7 +1,6 @@
 // SPDX-License-Identifier: CC0-1.0
 pragma solidity ^0.8.0;
 
-import "@openzeppelin/contracts/utils/Context.sol";
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 import "./AdminControlled.sol";
 import "./IExit.sol";
@@ -13,7 +12,7 @@ import "./IExit.sol";
  * Note they can later distribute these tokens as they wish using `transfer` and other
  * `ERC20` functions.
  */
-contract EvmErc20 is Context, ERC20, AdminControlled, IExit {
+contract EvmErc20 is ERC20, AdminControlled, IExit {
     uint8 private _decimals;
 
     constructor (string memory name, string memory symbol, uint8 decimal, address admin)  ERC20(name, symbol) AdminControlled(admin, 0) {
@@ -29,7 +28,7 @@ contract EvmErc20 is Context, ERC20, AdminControlled, IExit {
     }
 
     function withdrawToNear(bytes memory recipient, uint256 amount) external override {
-        _burn(msg.sender, amount);
+        _burn(_msgSender(), amount);
 
         bytes32 amount_b = bytes32(amount);
         bytes memory input = abi.encodePacked("\x01", amount_b, recipient);
@@ -41,7 +40,7 @@ contract EvmErc20 is Context, ERC20, AdminControlled, IExit {
     }
 
     function withdrawToEthereum(address recipient, uint256 amount) external override {
-        _burn(msg.sender, amount);
+        _burn(_msgSender(), amount);
 
         bytes32 amount_b = bytes32(amount);
         bytes20 recipient_b = bytes20(recipient);
diff --git a/etc/state-migration-test/Cargo.toml b/etc/state-migration-test/Cargo.toml
index 7a2bc3122..de0f11f77 100644
--- a/etc/state-migration-test/Cargo.toml
+++ b/etc/state-migration-test/Cargo.toml
@@ -38,4 +38,4 @@ rpath = false
 
 [dependencies]
 borsh = { version = "0.8.2", default-features = false }
-aurora-engine = { path = "../../", default-features = false, features = ["sha2", "engine"] }
+aurora-engine = { path = "../../", default-features = false, features = ["sha2"] }
diff --git a/src/connector.rs b/src/connector.rs
index 7a247da0c..1d6ad6c36 100644
--- a/src/connector.rs
+++ b/src/connector.rs
@@ -562,7 +562,7 @@ impl EthConnectorContract {
             _ => self.mint_eth_on_aurora(message_data.recipient, args.amount),
         }
         self.save_ft_contract();
-        sdk::return_output(0.to_string().as_bytes());
+        sdk::return_output("\"0\"".as_bytes());
     }
 
     /// Get accounts counter for statistics.
diff --git a/src/deposit_event.rs b/src/deposit_event.rs
index 0cfbf5887..39c80ecf6 100644
--- a/src/deposit_event.rs
+++ b/src/deposit_event.rs
@@ -46,7 +46,6 @@ impl DepositedEvent {
     }
 
     /// Parses raw Ethereum logs proof's entry data
-    #[cfg(feature = "engine")]
     pub fn from_log_entry_data(data: &[u8]) -> Self {
         let event = EthEvent::fetch_log_entry_data(DEPOSITED_EVENT, Self::event_params(), data);
         let sender = event.log.params[0].value.clone().into_address().unwrap().0;
diff --git a/src/engine.rs b/src/engine.rs
index edd172e52..30d415718 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -14,7 +14,7 @@ use crate::parameters::{
 };
 
 use crate::precompiles;
-use crate::prelude::{Address, ToString, TryInto, Vec, H256, U256};
+use crate::prelude::{Address, TryInto, Vec, H256, U256};
 use crate::sdk;
 use crate::state::AuroraStackState;
 use crate::storage::{address_to_key, bytes_to_key, storage_to_key, KeyPrefix, KeyPrefixU8};
@@ -500,7 +500,7 @@ impl Engine {
     /// IMPORTANT: This function should not panic, otherwise it won't
     /// be possible to return the tokens to the sender.
     pub fn receive_erc20_tokens(&mut self, args: &NEP141FtOnTransferArgs) {
-        let str_amount = args.amount.to_string();
+        let str_amount = crate::prelude::format!("\"{}\"", args.amount);
         let output_on_fail = str_amount.as_bytes();
 
         let token = sdk::predecessor_account_id();
@@ -576,8 +576,9 @@ impl Engine {
             output_on_fail
         );
 
+        // TODO(marX)
         // Everything succeed so return "0"
-        sdk::return_output(b"0");
+        sdk::return_output(b"\"0\"");
     }
 
     pub fn nep141_erc20_map() -> BijectionMap<
diff --git a/src/fungible_token.rs b/src/fungible_token.rs
index 4b18fd471..00ff7b5c0 100644
--- a/src/fungible_token.rs
+++ b/src/fungible_token.rs
@@ -2,19 +2,17 @@
 use crate::prelude::format;
 use crate::types::*;
 use borsh::{BorshDeserialize, BorshSerialize};
-#[cfg(feature = "engine")]
 use {
     crate::connector,
     crate::engine,
+    crate::json::parse_json,
     crate::parameters::*,
     crate::prelude::{self, Ordering, String, ToString, TryInto, Vec, U256},
     crate::sdk,
     crate::storage,
 };
 
-#[cfg(feature = "engine")]
 const GAS_FOR_RESOLVE_TRANSFER: Gas = 5_000_000_000_000;
-#[cfg(feature = "engine")]
 const GAS_FOR_FT_ON_TRANSFER: Gas = 10_000_000_000_000;
 
 #[derive(Debug, Default, BorshDeserialize, BorshSerialize)]
@@ -29,7 +27,6 @@ pub struct FungibleToken {
     pub account_storage_usage: StorageUsage,
 }
 
-#[cfg(feature = "engine")]
 impl FungibleToken {
     pub fn new() -> Self {
         Self::default()
@@ -245,12 +242,9 @@ impl FungibleToken {
         let unused_amount = match sdk::promise_result(0) {
             PromiseResult::NotReady => unreachable!(),
             PromiseResult::Successful(value) => {
-                if let Ok(unused_amount) = String::from_utf8(value) {
-                    let unused_amount = if let Ok(v) = unused_amount.parse::<u128>() {
-                        v
-                    } else {
-                        amount
-                    };
+                if let Some(unused_amount) =
+                    parse_json(value.as_slice()).and_then(|x| (&x).try_into().ok())
+                {
                     if amount > unused_amount {
                         unused_amount
                     } else {
@@ -382,7 +376,6 @@ impl FungibleToken {
         } else {
             let min_balance = self.storage_balance_bounds().min;
             if amount < min_balance {
-                #[cfg(feature = "log")]
                 sdk::panic_utf8(b"ERR_ATTACHED_DEPOSIT_NOT_ENOUGH");
             }
 
diff --git a/src/json.rs b/src/json.rs
index f6074f81b..d1bae1ca8 100644
--- a/src/json.rs
+++ b/src/json.rs
@@ -1,6 +1,5 @@
 use super::prelude::*;
 
-use alloc::collections::BTreeMap;
 use core::convert::From;
 use rjson::{Array, Null, Object, Value};
 
@@ -60,13 +59,7 @@ impl JsonValue {
     #[allow(dead_code)]
     pub fn u128(&self, key: &str) -> Result<u128, JsonError> {
         match self {
-            JsonValue::Object(o) => match o.get(key).ok_or(JsonError::MissingValue)? {
-                JsonValue::String(n) => {
-                    Ok(n.parse::<u128>().map_err(|_| JsonError::InvalidU128)?)
-                }
-                JsonValue::Number(_) => Err(JsonError::ExpectedStringGotNumber),
-                _ => Err(JsonError::InvalidU128),
-            },
+            JsonValue::Object(o) => o.get(key).ok_or(JsonError::MissingValue)?.try_into(),
             _ => Err(JsonError::NotJsonType),
         }
     }
@@ -177,6 +170,18 @@ impl From<JsonObject> for JsonValue {
     }
 }
 
+impl TryFrom<&JsonValue> for u128 {
+    type Error = JsonError;
+
+    fn try_from(value: &JsonValue) -> Result<Self, Self::Error> {
+        match value {
+            JsonValue::String(n) => Ok(n.parse::<u128>().map_err(|_| JsonError::InvalidU128)?),
+            JsonValue::Number(_) => Err(JsonError::ExpectedStringGotNumber),
+            _ => Err(JsonError::InvalidU128),
+        }
+    }
+}
+
 impl core::fmt::Debug for JsonValue {
     fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
         match *self {
diff --git a/src/lib.rs b/src/lib.rs
index 8ae87177a..0aae10d4f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -10,7 +10,6 @@ extern crate core;
 
 use crate::parameters::PromiseCreateArgs;
 
-#[cfg(feature = "engine")]
 mod map;
 #[cfg(feature = "meta-call")]
 pub mod meta_parsing;
@@ -20,27 +19,20 @@ pub mod storage;
 pub mod transaction;
 pub mod types;
 
-#[cfg(feature = "engine")]
 mod admin_controlled;
-#[cfg(feature = "engine")]
+#[cfg_attr(not(feature = "contract"), allow(dead_code))]
 mod connector;
 mod deposit_event;
-#[cfg(feature = "engine")]
 pub mod engine;
-#[cfg(any(feature = "engine", test))]
 mod fungible_token;
-#[cfg(feature = "engine")]
 mod json;
 mod log_entry;
 mod precompiles;
-#[cfg(feature = "engine")]
 mod prover;
-#[cfg(feature = "engine")]
 pub mod sdk;
 
 #[cfg(test)]
 mod benches;
-#[cfg(feature = "engine")]
 mod state;
 #[cfg(test)]
 mod test_utils;
diff --git a/src/parameters.rs b/src/parameters.rs
index f70ab06ea..69bd6e087 100644
--- a/src/parameters.rs
+++ b/src/parameters.rs
@@ -2,7 +2,6 @@ use borsh::{BorshDeserialize, BorshSerialize};
 
 use crate::prelude::{String, Vec};
 use crate::types::{AccountId, Balance, RawAddress, RawH256, RawU256};
-#[cfg(feature = "engine")]
 use crate::{
     admin_controlled::PausedMask,
     json,
@@ -142,7 +141,6 @@ pub struct NEP141FtOnTransferArgs {
     pub msg: String,
 }
 
-#[cfg(feature = "engine")]
 impl TryFrom<json::JsonValue> for NEP141FtOnTransferArgs {
     type Error = json::JsonError;
 
@@ -155,7 +153,6 @@ impl TryFrom<json::JsonValue> for NEP141FtOnTransferArgs {
     }
 }
 
-#[cfg(feature = "engine")]
 impl TryFrom<NEP141FtOnTransferArgs> for String {
     type Error = json::ParseError;
 
@@ -183,7 +180,6 @@ pub struct PromiseCreateArgs {
     pub attached_gas: u64,
 }
 /// Eth-connector deposit arguments
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct DepositCallArgs {
     /// Proof data
@@ -193,7 +189,6 @@ pub struct DepositCallArgs {
 }
 
 /// Eth-connector isUsedProof arguments
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct IsUsedProofCallArgs {
     /// Proof data
@@ -201,7 +196,6 @@ pub struct IsUsedProofCallArgs {
 }
 
 /// withdraw result for eth-connector
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize)]
 pub struct WithdrawResult {
     pub amount: Balance,
@@ -210,7 +204,6 @@ pub struct WithdrawResult {
 }
 
 /// ft_resolve_transfer eth-connector call args
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize)]
 pub struct FtResolveTransfer {
     pub receiver_id: AccountId,
@@ -219,18 +212,15 @@ pub struct FtResolveTransfer {
 }
 
 /// Fungible token storage balance
-#[cfg(feature = "engine")]
 #[derive(Default)]
 pub struct StorageBalance {
     pub total: Balance,
     pub available: Balance,
 }
 
-#[cfg(feature = "engine")]
 impl StorageBalance {
     pub fn to_json_bytes(&self) -> Vec<u8> {
-        use alloc::format;
-        format!(
+        crate::prelude::format!(
             "{{\"total\": \"{}\", \"available\": \"{}\",}}",
             self.total.to_string(),
             self.available.to_string()
@@ -241,7 +231,6 @@ impl StorageBalance {
 }
 
 /// resolve_transfer eth-connector call args
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct ResolveTransferCallArgs {
     pub sender_id: AccountId,
@@ -250,7 +239,6 @@ pub struct ResolveTransferCallArgs {
 }
 
 /// Finish deposit NEAR eth-connector call args
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct FinishDepositCallArgs {
     pub new_owner_id: AccountId,
@@ -262,7 +250,6 @@ pub struct FinishDepositCallArgs {
 }
 
 /// Deposit ETH args
-#[cfg(feature = "engine")]
 #[derive(Default, BorshDeserialize, BorshSerialize, Clone)]
 pub struct DepositEthCallArgs {
     pub proof: Proof,
@@ -270,7 +257,6 @@ pub struct DepositEthCallArgs {
 }
 
 /// Finish deposit NEAR eth-connector call args
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct FinishDepositEthCallArgs {
     pub new_owner_id: EthAddress,
@@ -291,7 +277,6 @@ pub struct InitCallArgs {
 pub type SetContractDataCallArgs = InitCallArgs;
 
 /// transfer eth-connector call args
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct TransferCallCallArgs {
     pub receiver_id: AccountId,
@@ -300,7 +285,6 @@ pub struct TransferCallCallArgs {
     pub msg: String,
 }
 
-#[cfg(feature = "engine")]
 impl From<json::JsonValue> for TransferCallCallArgs {
     fn from(v: json::JsonValue) -> Self {
         Self {
@@ -313,13 +297,11 @@ impl From<json::JsonValue> for TransferCallCallArgs {
 }
 
 /// storage_balance_of eth-connector call args
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct StorageBalanceOfCallArgs {
     pub account_id: AccountId,
 }
 
-#[cfg(feature = "engine")]
 impl From<json::JsonValue> for StorageBalanceOfCallArgs {
     fn from(v: json::JsonValue) -> Self {
         Self {
@@ -329,14 +311,12 @@ impl From<json::JsonValue> for StorageBalanceOfCallArgs {
 }
 
 /// storage_deposit eth-connector call args
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct StorageDepositCallArgs {
     pub account_id: Option<AccountId>,
     pub registration_only: Option<bool>,
 }
 
-#[cfg(feature = "engine")]
 impl From<json::JsonValue> for StorageDepositCallArgs {
     fn from(v: json::JsonValue) -> Self {
         Self {
@@ -347,13 +327,11 @@ impl From<json::JsonValue> for StorageDepositCallArgs {
 }
 
 /// storage_withdraw eth-connector call args
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct StorageWithdrawCallArgs {
     pub amount: Option<u128>,
 }
 
-#[cfg(feature = "engine")]
 impl From<json::JsonValue> for StorageWithdrawCallArgs {
     fn from(v: json::JsonValue) -> Self {
         Self {
@@ -363,7 +341,6 @@ impl From<json::JsonValue> for StorageWithdrawCallArgs {
 }
 
 /// transfer args for json invocation
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct TransferCallArgs {
     pub receiver_id: AccountId,
@@ -371,7 +348,6 @@ pub struct TransferCallArgs {
     pub memo: Option<String>,
 }
 
-#[cfg(feature = "engine")]
 impl From<json::JsonValue> for TransferCallArgs {
     fn from(v: json::JsonValue) -> Self {
         Self {
@@ -383,7 +359,6 @@ impl From<json::JsonValue> for TransferCallArgs {
 }
 
 /// withdraw NEAR eth-connector call args
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct WithdrawCallArgs {
     pub recipient_address: EthAddress,
@@ -391,19 +366,16 @@ pub struct WithdrawCallArgs {
 }
 
 /// balance_of args for json invocation
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct BalanceOfCallArgs {
     pub account_id: AccountId,
 }
 
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct BalanceOfEthCallArgs {
     pub address: EthAddress,
 }
 
-#[cfg(feature = "engine")]
 impl From<json::JsonValue> for BalanceOfCallArgs {
     fn from(v: json::JsonValue) -> Self {
         Self {
@@ -412,24 +384,20 @@ impl From<json::JsonValue> for BalanceOfCallArgs {
     }
 }
 
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct RegisterRelayerCallArgs {
     pub address: EthAddress,
 }
 
-#[cfg(feature = "engine")]
 #[derive(BorshSerialize, BorshDeserialize)]
 pub struct PauseEthConnectorCallArgs {
     pub paused_mask: PausedMask,
 }
 
-#[cfg(feature = "engine")]
 pub trait ExpectUtf8<T> {
     fn expect_utf8(self, message: &[u8]) -> T;
 }
 
-#[cfg(feature = "engine")]
 impl<T> ExpectUtf8<T> for Option<T> {
     fn expect_utf8(self, message: &[u8]) -> T {
         match self {
@@ -439,7 +407,6 @@ impl<T> ExpectUtf8<T> for Option<T> {
     }
 }
 
-#[cfg(feature = "engine")]
 impl<T, E> ExpectUtf8<T> for core::result::Result<T, E> {
     fn expect_utf8(self, message: &[u8]) -> T {
         match self {
@@ -449,7 +416,6 @@ impl<T, E> ExpectUtf8<T> for core::result::Result<T, E> {
     }
 }
 
-#[cfg(feature = "engine")]
 impl From<json::JsonValue> for ResolveTransferCallArgs {
     fn from(v: json::JsonValue) -> Self {
         Self {
diff --git a/src/precompiles/blake2.rs b/src/precompiles/blake2.rs
index 6511cc80d..f78b82fa2 100644
--- a/src/precompiles/blake2.rs
+++ b/src/precompiles/blake2.rs
@@ -18,7 +18,6 @@ mod consts {
 pub(super) struct Blake2F<S>(PhantomData<S>);
 
 impl<S> Blake2F<S> {
-    #[cfg_attr(not(feature = "engine"), allow(dead_code))]
     pub(super) const ADDRESS: [u8; 20] = super::make_address(0, 9);
 }
 
diff --git a/src/precompiles/bn128.rs b/src/precompiles/bn128.rs
index 3d352f127..73b46f57e 100644
--- a/src/precompiles/bn128.rs
+++ b/src/precompiles/bn128.rs
@@ -48,11 +48,8 @@ mod consts {
 pub(super) mod addresses {
     use crate::precompiles;
 
-    #[cfg_attr(not(feature = "engine"), allow(dead_code))]
     pub const ADD: [u8; 20] = precompiles::make_address(0, 6);
-    #[cfg_attr(not(feature = "engine"), allow(dead_code))]
     pub const MUL: [u8; 20] = precompiles::make_address(0, 7);
-    #[cfg_attr(not(feature = "engine"), allow(dead_code))]
     pub const PAIR: [u8; 20] = precompiles::make_address(0, 8);
 }
 
diff --git a/src/precompiles/hash.rs b/src/precompiles/hash.rs
index c0f437545..51ae03632 100644
--- a/src/precompiles/hash.rs
+++ b/src/precompiles/hash.rs
@@ -24,7 +24,6 @@ mod consts {
 pub struct SHA256<S>(PhantomData<S>);
 
 impl<S> SHA256<S> {
-    #[cfg_attr(not(feature = "engine"), allow(dead_code))]
     pub(super) const ADDRESS: [u8; 20] = super::make_address(0, 2);
 }
 
@@ -90,7 +89,6 @@ impl<S: AuroraState> Precompile<S> for SHA256<S> {
 pub struct RIPEMD160<S>(PhantomData<S>);
 
 impl<S> RIPEMD160<S> {
-    #[cfg_attr(not(feature = "engine"), allow(dead_code))]
     pub(super) const ADDRESS: [u8; 20] = super::make_address(0, 3);
 }
 
diff --git a/src/precompiles/identity.rs b/src/precompiles/identity.rs
index 36515505b..4053fe652 100644
--- a/src/precompiles/identity.rs
+++ b/src/precompiles/identity.rs
@@ -21,7 +21,6 @@ mod consts {
 pub struct Identity<S>(PhantomData<S>);
 
 impl<S> Identity<S> {
-    #[cfg_attr(not(feature = "engine"), allow(dead_code))]
     pub(super) const ADDRESS: [u8; 20] = super::make_address(0, 4);
 }
 
diff --git a/src/precompiles/mod.rs b/src/precompiles/mod.rs
index 4660303aa..de50d069c 100644
--- a/src/precompiles/mod.rs
+++ b/src/precompiles/mod.rs
@@ -3,6 +3,7 @@ mod bn128;
 mod hash;
 mod identity;
 mod modexp;
+#[cfg_attr(not(feature = "contract"), allow(dead_code))]
 mod native;
 mod secp256k1;
 use evm::{Context, ExitError};
@@ -10,7 +11,6 @@ use evm::{Context, ExitError};
 pub(crate) use crate::precompiles::secp256k1::ecrecover;
 use crate::prelude::Vec;
 use crate::AuroraState;
-#[cfg(feature = "engine")]
 use crate::{
     precompiles::blake2::Blake2F,
     precompiles::bn128::{BN128Add, BN128Mul, BN128Pair},
@@ -66,7 +66,6 @@ impl From<PrecompileOutput> for evm::executor::PrecompileOutput {
 /// A precompile operation result.
 type PrecompileResult = Result<PrecompileOutput, ExitError>;
 
-#[cfg(feature = "engine")]
 type EvmPrecompileResult = Result<evm::executor::PrecompileOutput, ExitError>;
 
 /// A precompiled function for use in the EVM.
@@ -211,7 +210,6 @@ pub fn byzantium_precompiles(
 }
 
 /// Matches the address given to Istanbul precompiles.
-#[cfg(feature = "engine")]
 #[allow(dead_code)]
 pub fn istanbul_precompiles(
     address: Address,
@@ -323,7 +321,6 @@ pub fn berlin_precompiles(
 /// const fn for making an address by concatenating the bytes from two given numbers,
 /// Note that 32 + 128 = 160 = 20 bytes (the length of an address). This function is used
 /// as a convenience for specifying the addresses of the various precompiles.
-#[cfg_attr(not(feature = "engine"), allow(dead_code))]
 const fn make_address(x: u32, y: u128) -> [u8; 20] {
     let x_bytes = x.to_be_bytes();
     let y_bytes = y.to_be_bytes();
diff --git a/src/precompiles/modexp.rs b/src/precompiles/modexp.rs
index 26410f054..c1be8dbc8 100644
--- a/src/precompiles/modexp.rs
+++ b/src/precompiles/modexp.rs
@@ -6,7 +6,6 @@ use crate::AuroraState;
 use evm::{Context, ExitError};
 use num::{BigUint, Integer};
 
-#[cfg_attr(not(feature = "engine"), allow(dead_code))]
 pub(super) const ADDRESS: [u8; 20] = super::make_address(0, 5);
 
 pub(super) struct ModExp<HF: HardFork, S>(PhantomData<HF>, PhantomData<S>);
diff --git a/src/precompiles/native.rs b/src/precompiles/native.rs
index 9b3382eae..c03b12553 100644
--- a/src/precompiles/native.rs
+++ b/src/precompiles/native.rs
@@ -4,7 +4,7 @@ use crate::prelude::PhantomData;
 #[cfg(not(feature = "contract"))]
 use crate::prelude::Vec;
 use crate::AuroraState;
-#[cfg(feature = "engine")]
+#[cfg(feature = "contract")]
 use {
     crate::parameters::PromiseCreateArgs,
     crate::parameters::WithdrawCallArgs,
@@ -16,7 +16,6 @@ use {
 
 use super::{Precompile, PrecompileResult};
 
-#[cfg_attr(not(feature = "engine"), allow(dead_code))]
 const ERR_TARGET_TOKEN_NOT_FOUND: &str = "Target token not found";
 
 use crate::precompiles::PrecompileOutput;
@@ -31,11 +30,9 @@ mod costs {
     pub(super) const EXIT_TO_ETHEREUM_GAS: Gas = 0;
 
     // TODO(#51): Determine the correct amount of gas
-    #[cfg_attr(not(feature = "engine"), allow(dead_code))]
     pub(super) const FT_TRANSFER_GAS: Gas = 100_000_000_000_000;
 
     // TODO(#51): Determine the correct amount of gas
-    #[cfg_attr(not(feature = "engine"), allow(dead_code))]
     pub(super) const WITHDRAWAL_GAS: Gas = 100_000_000_000_000;
 }
 
@@ -46,7 +43,6 @@ impl<S> ExitToNear<S> {
     ///
     /// Address: `0xe9217bc70b7ed1f598ddd3199e80b093fa71124f`
     /// This address is computed as: `&keccak("exitToNear")[12..]`
-    #[cfg_attr(not(feature = "engine"), allow(dead_code))]
     pub(super) const ADDRESS: [u8; 20] =
         super::make_address(0xe9217bc7, 0x0b7ed1f598ddd3199e80b093fa71124f);
 }
@@ -194,7 +190,6 @@ impl<S> ExitToEthereum<S> {
     ///
     /// Address: `0xb0bd02f6a392af548bdf1cfaee5dfa0eefcc8eab`
     /// This address is computed as: `&keccak("exitToEthereum")[12..]`
-    #[cfg_attr(not(feature = "engine"), allow(dead_code))]
     pub(super) const ADDRESS: [u8; 20] =
         super::make_address(0xb0bd02f6, 0xa392af548bdf1cfaee5dfa0eefcc8eab);
 }
@@ -329,21 +324,19 @@ impl<S: AuroraState> Precompile<S> for ExitToEthereum<S> {
     }
 }
 
-#[cfg(all(feature = "contract", test))]
+#[cfg(test)]
 mod tests {
     use super::{ExitToEthereum, ExitToNear};
     use crate::types::near_account_to_evm_address;
 
-    use super::*;
-
     #[test]
     fn test_precompile_id() {
         assert_eq!(
-            ExitToEthereum::ADDRESS,
+            ExitToEthereum::<()>::ADDRESS,
             near_account_to_evm_address("exitToEthereum".as_bytes()).0
         );
         assert_eq!(
-            ExitToNear::ADDRESS,
+            ExitToNear::<()>::ADDRESS,
             near_account_to_evm_address("exitToNear".as_bytes()).0
         );
     }
diff --git a/src/precompiles/secp256k1.rs b/src/precompiles/secp256k1.rs
index 15b764883..f82f545ae 100644
--- a/src/precompiles/secp256k1.rs
+++ b/src/precompiles/secp256k1.rs
@@ -44,7 +44,6 @@ pub fn ecrecover(hash: H256, signature: &[u8]) -> Result<Address, ExitError> {
 pub(super) struct ECRecover<S>(PhantomData<S>);
 
 impl<S> ECRecover<S> {
-    #[cfg_attr(not(feature = "engine"), allow(dead_code))]
     pub(super) const ADDRESS: [u8; 20] = super::make_address(0, 1);
 }
 
diff --git a/src/prelude.rs b/src/prelude.rs
index d76444da4..fb55e90be 100644
--- a/src/prelude.rs
+++ b/src/prelude.rs
@@ -4,6 +4,7 @@ pub use alloc::{
     borrow::{Cow, Cow::*},
     boxed::Box,
     collections::BTreeMap as HashMap,
+    collections::BTreeMap,
     fmt, format, str,
     string::String,
     string::ToString,
diff --git a/src/sdk.rs b/src/sdk.rs
index 7c3b80168..8a78c3124 100644
--- a/src/sdk.rs
+++ b/src/sdk.rs
@@ -173,11 +173,13 @@ pub fn read_input() -> Vec<u8> {
     }
 }
 
+#[cfg_attr(not(feature = "contract"), allow(dead_code))]
 pub(crate) fn read_input_borsh<T: BorshDeserialize>() -> Result<T, ArgParseErr> {
     let bytes = read_input();
     T::try_from_slice(&bytes).map_err(|_| ArgParseErr)
 }
 
+#[cfg_attr(not(feature = "contract"), allow(dead_code))]
 pub(crate) fn read_input_arr20() -> Result<[u8; 20], IncorrectInputLength> {
     unsafe {
         exports::input(INPUT_REGISTER_ID);
diff --git a/src/test_utils/exit_precompile.rs b/src/test_utils/exit_precompile.rs
index 3892cefef..6149529d4 100644
--- a/src/test_utils/exit_precompile.rs
+++ b/src/test_utils/exit_precompile.rs
@@ -2,8 +2,6 @@ use crate::parameters::SubmitResult;
 use crate::prelude::{Address, U256};
 use crate::test_utils::{solidity, AuroraRunner, Signer};
 use crate::transaction::EthTransaction;
-#[cfg(feature = "engine")]
-use {crate::parameters::FunctionCallArgs, borsh::BorshSerialize, std::convert::TryInto};
 
 pub(crate) struct TesterConstructor(pub solidity::ContractConstructor);
 
diff --git a/src/test_utils/mod.rs b/src/test_utils/mod.rs
index 9f6bf6708..89ff97224 100644
--- a/src/test_utils/mod.rs
+++ b/src/test_utils/mod.rs
@@ -103,7 +103,8 @@ impl<'a> OneShotAuroraRunner<'a> {
         );
 
         near_vm_runner::run(
-            &self.base.code,
+            self.base.code.hash.as_ref().to_vec(),
+            &self.base.code.code.as_slice(),
             method_name,
             &mut self.ext,
             self.context.clone(),
@@ -168,7 +169,8 @@ impl AuroraRunner {
         );
 
         let (maybe_outcome, maybe_error) = near_vm_runner::run(
-            &self.code,
+            self.code.hash.as_ref().to_vec(),
+            &self.code.code.as_slice(),
             method_name,
             &mut self.ext,
             self.context.clone(),
@@ -275,7 +277,8 @@ impl AuroraRunner {
             address.as_bytes().to_vec(),
         );
         let (outcome, maybe_error) = near_vm_runner::run(
-            &self.code,
+            self.code.hash.as_ref().to_vec(),
+            &self.code.code.as_slice(),
             method_name,
             &mut self.ext.clone(),
             context,
diff --git a/src/tests/contract_call.rs b/src/tests/contract_call.rs
index 02e8da91f..531da120f 100644
--- a/src/tests/contract_call.rs
+++ b/src/tests/contract_call.rs
@@ -2,15 +2,6 @@ use crate::test_utils::{origin, AuroraRunner, Signer};
 
 use crate::test_utils;
 use crate::test_utils::exit_precompile::{Tester, TesterConstructor};
-#[cfg(feature = "engine")]
-use {
-    crate::prelude::U256,
-    crate::test_utils::solidity,
-    crate::transaction::EthTransaction,
-    ethabi::Address,
-    near_crypto::SecretKey,
-    std::path::{Path, PathBuf},
-};
 
 fn setup_test() -> (AuroraRunner, Signer, [u8; 20], Tester) {
     let mut runner = AuroraRunner::new();
diff --git a/src/tests/erc20_connector.rs b/src/tests/erc20_connector.rs
index fbd89857e..4bb6106e0 100644
--- a/src/tests/erc20_connector.rs
+++ b/src/tests/erc20_connector.rs
@@ -272,7 +272,7 @@ fn test_ft_on_transfer() {
 
     let res = runner.ft_on_transfer(nep141, alice.clone(), alice, amount, hex::encode(recipient));
     // Transaction should succeed so return amount is 0
-    assert_eq!(res, "0");
+    assert_eq!(res, "\"0\"");
 
     let balance = runner.balance_of(token, recipient, origin());
     assert_eq!(balance, U256::from(amount));
@@ -290,7 +290,7 @@ fn test_ft_on_transfer_fail() {
     let res = runner.ft_on_transfer(nep141, alice.clone(), alice, amount, hex::encode(recipient));
 
     // Transaction should fail so it must return everything
-    assert_eq!(res, amount.to_string());
+    assert_eq!(res, format!("\"{}\"", amount.to_string()));
 }
 
 #[test]
diff --git a/tests/test_meta_parsing.rs b/src/tests/meta_parsing.rs
similarity index 86%
rename from tests/test_meta_parsing.rs
rename to src/tests/meta_parsing.rs
index 19f315ca8..0af48d49e 100644
--- a/tests/test_meta_parsing.rs
+++ b/src/tests/meta_parsing.rs
@@ -1,20 +1,13 @@
-#[cfg(feature = "meta-call")]
 use {
-    aurora_engine::meta_parsing::{near_erc712_domain, parse_meta_call, prepare_meta_call_args},
-    aurora_engine::parameters::MetaCallArgs,
-    aurora_engine::prelude::U256,
-    aurora_engine::types::{u256_to_arr, InternalMetaCallArgs, Wei},
+    crate::meta_parsing::{near_erc712_domain, parse_meta_call, prepare_meta_call_args},
+    crate::parameters::MetaCallArgs,
+    crate::prelude::{Address, U256},
+    crate::types::{keccak, u256_to_arr, InternalMetaCallArgs, Wei},
     borsh::BorshSerialize,
-    near_crypto::{InMemorySigner, KeyType, Signature, Signer},
+    near_crypto::{InMemorySigner, KeyType, PublicKey, Signature, Signer},
 };
 
-use near_crypto::PublicKey;
-
-use aurora_engine::prelude::Address;
-use aurora_engine::types::keccak;
-
-#[cfg(feature = "meta-call")]
-pub fn encode_meta_call_function_args(
+fn encode_meta_call_function_args(
     signer: &dyn Signer,
     chain_id: u64,
     nonce: U256,
@@ -67,7 +60,7 @@ pub fn encode_meta_call_function_args(
     }
 }
 
-pub fn public_key_to_address(public_key: PublicKey) -> Address {
+fn public_key_to_address(public_key: PublicKey) -> Address {
     match public_key {
         PublicKey::ED25519(_) => panic!("Wrong PublicKey"),
         PublicKey::SECP256K1(pubkey) => {
@@ -80,7 +73,7 @@ pub fn public_key_to_address(public_key: PublicKey) -> Address {
     }
 }
 
-#[cfg(all(feature = "meta-call", test))]
+#[test]
 fn test_meta_parsing() {
     let chain_id = 1313161555;
     let signer = InMemorySigner::from_seed("doesnt", KeyType::SECP256K1, "a");
diff --git a/src/tests/mod.rs b/src/tests/mod.rs
index 3705e2c25..6d11fe463 100644
--- a/src/tests/mod.rs
+++ b/src/tests/mod.rs
@@ -1,6 +1,9 @@
 mod contract_call;
 mod erc20;
 mod erc20_connector;
+#[cfg(feature = "meta-call")]
+mod meta_parsing;
 mod sanity;
 mod self_destruct_state;
 mod standard_precompiles;
+mod state_migration;
diff --git a/tests/test_state_migration.rs b/src/tests/state_migration.rs
similarity index 72%
rename from tests/test_state_migration.rs
rename to src/tests/state_migration.rs
index ecbdae253..1be240a31 100644
--- a/tests/test_state_migration.rs
+++ b/src/tests/state_migration.rs
@@ -1,19 +1,13 @@
-use aurora_engine::parameters::NewCallArgs;
-use aurora_engine::prelude::U256;
-use aurora_engine::types;
+use crate::parameters::NewCallArgs;
+use crate::prelude::U256;
+use crate::test_utils::AuroraRunner;
+use crate::types;
 use borsh::BorshSerialize;
 use near_sdk_sim::{ExecutionResult, UserAccount};
 use std::fs;
 use std::path::Path;
 use std::process::Command;
 
-// TODO: it would be nice to include this under src/tests but right now this is not possible.
-// The issue is a linker error (arising from multiple dependencies on near-vm-logic I think).
-
-near_sdk_sim::lazy_static_include::lazy_static_include_bytes! {
-    EVM_WASM_BYTES => "release.wasm"
-}
-
 #[test]
 fn test_state_migration() {
     let aurora = deploy_evm();
@@ -33,15 +27,15 @@ fn test_state_migration() {
 }
 
 fn deploy_evm() -> AuroraAccount {
-    let aurora_config = AuroraConfig::default();
+    let aurora_runner = AuroraRunner::default();
     let main_account = near_sdk_sim::init_simulator(None);
     let contract_account = main_account.deploy(
-        &aurora_config.code,
-        aurora_config.account_id.clone(),
+        &aurora_runner.code.code,
+        aurora_runner.aurora_account_id.clone(),
         5 * near_sdk_sim::STORAGE_AMOUNT,
     );
     let new_args = NewCallArgs {
-        chain_id: types::u256_to_arr(&U256::from(aurora_config.chain_id)),
+        chain_id: types::u256_to_arr(&U256::from(aurora_runner.chain_id)),
         owner_id: main_account.account_id.clone(),
         bridge_prover_id: "prover.near".to_string(),
         upgrade_delay_blocks: 1,
@@ -78,22 +72,6 @@ impl AuroraAccount {
     }
 }
 
-struct AuroraConfig {
-    code: Vec<u8>,
-    chain_id: u64,
-    account_id: String,
-}
-
-impl Default for AuroraConfig {
-    fn default() -> Self {
-        Self {
-            code: EVM_WASM_BYTES.to_vec(),
-            chain_id: 1313161556, // NEAR betanet
-            account_id: "aurora".to_string(),
-        }
-    }
-}
-
 fn contract_bytes() -> Vec<u8> {
     let base_path = Path::new("etc").join("state-migration-test");
     let output_path = base_path
diff --git a/src/types.rs b/src/types.rs
index bf165650b..582afe8aa 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -12,10 +12,8 @@ use ethabi::{ParamType, Token};
 #[cfg(not(feature = "contract"))]
 use sha3::{Digest, Keccak256};
 
-#[cfg(feature = "engine")]
 use crate::engine::EngineResult;
 use crate::log_entry::LogEntry;
-#[cfg(feature = "engine")]
 use crate::sdk;
 
 #[cfg(not(feature = "contract"))]
@@ -24,7 +22,7 @@ use ethabi::param_type::Writer;
 pub type AccountId = String;
 pub type Balance = u128;
 pub type RawAddress = [u8; 20];
-pub type RawU256 = [u8; 32]; // Little-endian large integer type.
+pub type RawU256 = [u8; 32]; // Big-endian large integer type.
 pub type RawH256 = [u8; 32]; // Unformatted binary data of fixed length.
 pub type EthAddress = [u8; 20];
 pub type Gas = u64;
@@ -207,7 +205,6 @@ pub struct StorageBalanceBounds {
 }
 
 /// promise results structure
-#[cfg(feature = "engine")]
 pub enum PromiseResult {
     NotReady,
     Successful(Vec<u8>),
@@ -215,7 +212,6 @@ pub enum PromiseResult {
 }
 
 /// ft_resolve_transfer result of eth-connector
-#[cfg(feature = "engine")]
 pub struct FtResolveTransferResult {
     pub amount: Balance,
     pub refund_amount: Balance,
@@ -302,7 +298,6 @@ impl<T> Stack<T> {
         self.stack
     }
 }
-#[cfg(feature = "engine")]
 pub fn str_from_slice(inp: &[u8]) -> &str {
     str::from_utf8(inp).unwrap()
 }
@@ -332,12 +327,10 @@ impl<T, E> ExpectUtf8<T> for core::result::Result<T, E> {
     }
 }
 
-#[cfg(feature = "engine")]
 pub trait SdkExpect<T> {
     fn sdk_expect(self, msg: &str) -> T;
 }
 
-#[cfg(feature = "engine")]
 impl<T> SdkExpect<T> for Option<T> {
     fn sdk_expect(self, msg: &str) -> T {
         match self {
@@ -347,7 +340,6 @@ impl<T> SdkExpect<T> for Option<T> {
     }
 }
 
-#[cfg(feature = "engine")]
 impl<T, E> SdkExpect<T> for core::result::Result<T, E> {
     fn sdk_expect(self, msg: &str) -> T {
         match self {
@@ -357,12 +349,10 @@ impl<T, E> SdkExpect<T> for core::result::Result<T, E> {
     }
 }
 
-#[cfg(feature = "engine")]
 pub trait SdkUnwrap<T> {
     fn sdk_unwrap(self) -> T;
 }
 
-#[cfg(feature = "engine")]
 impl<T> SdkUnwrap<T> for Option<T> {
     fn sdk_unwrap(self) -> T {
         match self {
@@ -372,7 +362,6 @@ impl<T> SdkUnwrap<T> for Option<T> {
     }
 }
 
-#[cfg(feature = "engine")]
 impl<T, E: AsRef<[u8]>> SdkUnwrap<T> for core::result::Result<T, E> {
     fn sdk_unwrap(self) -> T {
         match self {
@@ -382,12 +371,10 @@ impl<T, E: AsRef<[u8]>> SdkUnwrap<T> for core::result::Result<T, E> {
     }
 }
 
-#[cfg(feature = "engine")]
 pub(crate) trait SdkProcess<T> {
     fn sdk_process(self);
 }
 
-#[cfg(feature = "engine")]
 impl<T: AsRef<[u8]>> SdkProcess<T> for EngineResult<T> {
     fn sdk_process(self) {
         match self {
diff --git a/tests/test_upgrade.rs b/tests/test_upgrade.rs
deleted file mode 100644
index 2bfff9e9d..000000000
--- a/tests/test_upgrade.rs
+++ /dev/null
@@ -1,55 +0,0 @@
-use near_sdk::borsh::BorshSerialize;
-use near_sdk::test_utils::accounts;
-use near_sdk_sim::{to_yocto, UserAccount, DEFAULT_GAS, STORAGE_AMOUNT};
-
-use aurora_engine::parameters::NewCallArgs;
-
-near_sdk_sim::lazy_static_include::lazy_static_include_bytes! {
-    EVM_WASM_BYTES => "release.wasm"
-}
-
-pub fn init() -> (UserAccount, UserAccount) {
-    let master_account = near_sdk_sim::init_simulator(None);
-    let contract_account =
-        master_account.deploy(*EVM_WASM_BYTES, accounts(0).to_string(), to_yocto("1000"));
-    contract_account
-        .call(
-            accounts(0).to_string(),
-            "new",
-            &NewCallArgs {
-                chain_id: [0u8; 32],
-                owner_id: master_account.account_id.clone(),
-                bridge_prover_id: accounts(0).to_string(),
-                upgrade_delay_blocks: 1,
-            }
-            .try_to_vec()
-            .unwrap(),
-            DEFAULT_GAS,
-            STORAGE_AMOUNT,
-        )
-        .assert_success();
-    (master_account, contract_account)
-}
-
-#[test]
-fn test_contract_upgrade() {
-    let (master_account, _contract_account) = init();
-    master_account
-        .call(
-            accounts(0).to_string(),
-            "stage_upgrade",
-            &EVM_WASM_BYTES,
-            DEFAULT_GAS,
-            0,
-        )
-        .assert_success();
-    master_account
-        .call(
-            accounts(0).to_string(),
-            "deploy_upgrade",
-            &[],
-            DEFAULT_GAS,
-            0,
-        )
-        .assert_success();
-}